From b783deab36d1f8993b6883c63371f2b278ef18fc Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 13:51:04 +0200
Subject: [PATCH 1/7] hm2_eth: Use library for EVL support

A library is needed to avoid having to link hm2_eth to libevl
and being able to create a package not depending on libevl.
---
 src/Makefile                                  | 11 ++--
 src/hal/drivers/Submakefile                   | 11 ++++
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 61 ++++++++++++++++---
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   |  1 +
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.c |  3 +
 5 files changed, 71 insertions(+), 16 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 2c56a18ed3a..ef7ba15b609 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1080,11 +1080,8 @@ hm2_pci-objs  :=			  \
     $(MATHSTUB)
 hm2_eth-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_eth.o   \
-    hal/drivers/mesa-hostmot2/hm2_eth_net_posix.o
-ifeq ($(CONFIG_USPACE_XENOMAI_EVL),y)
-hm2_eth-objs  += hal/drivers/mesa-hostmot2/hm2_eth_net_evl.o
-endif
-hm2_eth-objs  += $(MATHSTUB)
+    hal/drivers/mesa-hostmot2/hm2_eth_net_posix.o \
+    $(MATHSTUB)
 hm2_spi-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_spi.o   \
     hal/drivers/mesa-hostmot2/llio_info.o \
@@ -1329,7 +1326,7 @@ modules: $(patsubst %.o,../rtlib/%.so,$(obj-m))
 	$(Q)objdump -w -j .rtapi_export -t objects/$*.tmp \
 	| awk 'BEGIN{print "{ global :"} /rtapi_exported_/{printf("%s;\n", substr($$6,16))} END{print "local : * ; };"}' \
 	> objects/$*.ver
-	$(Q)$(CC) -shared -Bsymbolic -Wl,--version-script,objects/$*.ver -o $@ $^ -lm $(XENOMAI_EVL_LDFLAGS) $(LDFLAGS)
+	$(Q)$(CC) -shared -Bsymbolic -Wl,--version-script,objects/$*.ver -o $@ $^ -lm $(LDFLAGS)
 	$(Q)chmod -x $@
 
 RTFLAGS += -fno-strict-aliasing -fwrapv
@@ -1340,7 +1337,7 @@ $(sort $(filter-out objects/rtemc/tp/cruckig/%,$(RTOBJS))) : objects/rt%.o : %.c
 	@rm -f $@
 	@mkdir -p $(dir $@)
 	$(Q)$(CC) -c $(OPT) $(DEBUG) $(EXTRA_DEBUG) -DRTAPI \
-		$(EXTRA_CFLAGS) $(XENOMAI_EVL_CFLAGS) \
+		$(EXTRA_CFLAGS) \
 		-MP -MD -MF "${@:.o=.d}" -MT "$@" \
 		$< -o $@
 
diff --git a/src/hal/drivers/Submakefile b/src/hal/drivers/Submakefile
index b4ff16113ef..aab6f9dd3ac 100644
--- a/src/hal/drivers/Submakefile
+++ b/src/hal/drivers/Submakefile
@@ -39,3 +39,14 @@ modules:                                                         \
     hal/drivers/pluto_step_rbf.h
 endif
 
+
+ifeq ($(CONFIG_USPACE_XENOMAI_EVL),y)
+NET_EVL_SRCS := hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+USERSRCS += $(NET_EVL_SRCS)
+$(call TOOBJSDEPS, $(NET_EVL_SRCS)): EXTRAFLAGS += -fPIC $(XENOMAI_EVL_CFLAGS)
+../lib/liblinuxcnc-hm2_eth_net_evl.so.0: $(call TOOBJS, $(NET_EVL_SRCS))
+	$(ECHO) Linking $(notdir $@)
+	$(Q)$(CXX) -shared $(LDFLAGS) -o $@ $^ $(XENOMAI_EVL_LDFLAGS) -Wl,-soname,$(notdir $@)
+TARGETS += ../lib/liblinuxcnc-hm2_eth_net_evl.so.0
+TARGETS += ../lib/liblinuxcnc-hm2_eth_net_evl.so
+endif
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index 5dbf3cfae9a..bee0a7e09ba 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -32,6 +32,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <assert.h>
+#include <dlfcn.h>
 
 #include <rtapi_slab.h>
 #include <rtapi_ctype.h>
@@ -44,15 +45,19 @@
 
 #include <hal.h>
 
-#include "config.h" //For USPACE_XENOMAI_EVL
+#include "config.h" //For USPACE_XENOMAI_EVL defines
 
 #include "hostmot2-lowlevel.h"
 #include "hostmot2.h"
 #include "hm2_eth.h"
 #include "hm2_eth_net_posix.h"
-#ifdef USPACE_XENOMAI_EVL
-#include "hm2_eth_net_evl.h"
-#endif
+
+EXPORT_SYMBOL(use_firewall);
+EXPORT_SYMBOL(install_firewall_board);
+EXPORT_SYMBOL(install_firewall_perinterface);
+EXPORT_SYMBOL(clear_firewall);
+EXPORT_SYMBOL(fetch_ifname);
+EXPORT_SYMBOL(fetch_hwaddr);
 
 #define RECV_TIMEOUT_NON_RT_NS (200 * 1000 * 1000) //200ms for initialisation / non-realtime part
 
@@ -815,6 +820,21 @@ int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
     return 0;
 }
 
+#ifdef USPACE_XENOMAI_EVL
+static void *eth_net_evl_lib = NULL;
+static bool load_eth_net_evl(void) {
+    if (eth_net_evl_lib != NULL) {
+        return true; // Already checked
+    }
+    eth_net_evl_lib = dlopen("liblinuxcnc-hm2_eth_net_evl.so", RTLD_LOCAL | RTLD_NOW);
+    if (!eth_net_evl_lib) {
+        LL_PRINT("ERROR: EVL support loading library failed: %s\n", dlerror());
+        return false;
+    }
+    return true;
+}
+#endif
+
 static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_rtnet){
     //Default (NULL) is posix
     if (board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0) {
@@ -829,11 +849,34 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
             LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC not running with Xenomai4 EVL realtime\n", board_rtnet)
             return -1;
         }
-        board->init_board = &hm2_evl_init_board;
-        board->init_board_realtime = &hm2_evl_init_board_realtime;
-        board->close_board = &hm2_evl_close_board;
-        board->eth_socket_send = &hm2_evl_eth_socket_send;
-        board->eth_socket_recv = &hm2_evl_eth_socket_recv;
+        if (!load_eth_net_evl()) {
+            return -1;
+        }
+        board->init_board = dlsym(eth_net_evl_lib, "hm2_evl_init_board");
+        if (board->init_board == NULL) {
+            LL_PRINT("ERROR: EVL support dlsym hm2_evl_init_board failed: %s\n", dlerror());
+            return -1;
+        }
+        board->init_board_realtime = dlsym(eth_net_evl_lib, "hm2_evl_init_board_realtime");
+        if (board->init_board_realtime == NULL) {
+            LL_PRINT("ERROR: EVL support dlsym init_board_realtime failed: %s\n", dlerror());
+            return -1;
+        }
+        board->close_board = dlsym(eth_net_evl_lib, "hm2_evl_close_board");
+        if (board->close_board == NULL) {
+            LL_PRINT("ERROR: EVL support dlsym hm2_evl_init_close_boardboard failed: %s\n", dlerror());
+            return -1;
+        }
+        board->eth_socket_send = dlsym(eth_net_evl_lib, "hm2_evl_eth_socket_send");
+        if (board->eth_socket_send == NULL) {
+            LL_PRINT("ERROR: EVL support dlsym eth_socket_send failed: %s\n", dlerror());
+            return -1;
+        }
+        board->eth_socket_recv = dlsym(eth_net_evl_lib, "hm2_evl_eth_socket_recv");
+        if (board->eth_socket_recv == NULL) {
+            LL_PRINT("ERROR: EVL support dlsym eth_socket_recv failed: %s\n", dlerror());
+            return -1;
+        }
 #else
         LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC was built without Xenomai EVL support\n", board_rtnet);
         return -1;
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index 38958f7e659..e90b84e1c6f 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -340,3 +340,4 @@ int hm2_evl_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int recv_ti
     }
     return ret;
 }
+
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index 43ae1358ec2..0397536e058 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -35,6 +35,9 @@
 #define SEND_TIMEOUT_US 10
 #define RECV_TIMEOUT_US 10
 
+EXPORT_SYMBOL(hm2_posix_eth_socket_send);
+EXPORT_SYMBOL(hm2_posix_eth_socket_recv);
+
 /// ethernet io functions
 
 int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {

From 80b7f8d77f2a5af9c26139329dad7af742a778df Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 13:56:00 +0200
Subject: [PATCH 2/7] hm2_eth: Rename exported functions

...so they are less likely to conflict and remove not
externaly used install_firewall_perinterface from header.
---
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 33 +++++++++----------
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       | 11 +++----
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   | 10 +++---
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.c | 10 +++---
 4 files changed, 31 insertions(+), 33 deletions(-)

diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index bee0a7e09ba..43543766188 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -52,12 +52,11 @@
 #include "hm2_eth.h"
 #include "hm2_eth_net_posix.h"
 
-EXPORT_SYMBOL(use_firewall);
-EXPORT_SYMBOL(install_firewall_board);
-EXPORT_SYMBOL(install_firewall_perinterface);
-EXPORT_SYMBOL(clear_firewall);
-EXPORT_SYMBOL(fetch_ifname);
-EXPORT_SYMBOL(fetch_hwaddr);
+EXPORT_SYMBOL(hm2_eth_use_firewall);
+EXPORT_SYMBOL(hm2_eth_install_firewall_board);
+EXPORT_SYMBOL(hm2_eth_clear_firewall);
+EXPORT_SYMBOL(hm2_eth_fetch_ifname);
+EXPORT_SYMBOL(hm2_eth_fetch_hwaddr);
 
 #define RECV_TIMEOUT_NON_RT_NS (200 * 1000 * 1000) //200ms for initialisation / non-realtime part
 
@@ -596,7 +595,7 @@ static fw_state_t fw_state = FW_UNRESOLVED;
 // Resolve and bring up the firewall backend on first call, caching the
 // result.  Returns true when a backend is ready, false when isolation
 // is unavailable or disabled.
-bool use_firewall() {
+bool hm2_eth_use_firewall() {
     if(fw_state != FW_UNRESOLVED)
         return fw_state == FW_READY;
 
@@ -643,8 +642,8 @@ bool use_firewall() {
 
 // Drop all rules from our chain/table but keep the chain in place, so a
 // fresh set can be installed on (re-)init.
-void clear_firewall() {
-    if(!use_firewall()) return;
+void hm2_eth_clear_firewall() {
+    if(!hm2_eth_use_firewall()) return;
     switch(fw_backend) {
     case FW_IPTABLES:
         IPT(1, "-F", CHAIN);
@@ -660,7 +659,7 @@ void clear_firewall() {
 
 // Remove everything we installed: chain, OUTPUT jump, and (nft) table.
 static void cleanup_firewall() {
-    if(!use_firewall()) return;
+    if(!hm2_eth_use_firewall()) return;
     switch(fw_backend) {
     case FW_IPTABLES:
         IPT(1, "-F", CHAIN);
@@ -684,7 +683,7 @@ static char* inet_ntoa_buf(struct in_addr in, char *buf, size_t n) {
     return buf;
 }
 
-char* fetch_ifname(int sockfd, char *buf, size_t n) {
+char* hm2_eth_fetch_ifname(int sockfd, char *buf, size_t n) {
     struct sockaddr_in srcaddr;
     struct ifaddrs *ifa, *it;
 
@@ -711,12 +710,12 @@ char* fetch_ifname(int sockfd, char *buf, size_t n) {
     return NULL;
 }
 
-int install_firewall_board(int sockfd) {
+int hm2_eth_install_firewall_board(int sockfd) {
     struct sockaddr_in srcaddr, dstaddr;
     char srchost[16], dsthost[16]; // enough for 255.255.255.255\0
     char dport_s[8], sport_s[8];
 
-    if(!use_firewall()) return 0;
+    if(!hm2_eth_use_firewall()) return 0;
 
     socklen_t addrlen = sizeof(srcaddr);
     int res = getsockname(sockfd, &srcaddr, &addrlen);
@@ -756,7 +755,7 @@ int install_firewall_board(int sockfd) {
     return 0;
 }
 
-int install_firewall_perinterface(const char *ifbuf) {
+static int install_firewall_perinterface(const char *ifbuf) {
     // Without these rules, 'ping' spews a lot of "Packet filtered"
     // messages.  With them, ping prints 'ping: sendmsg: Operation not
     // permitted' once per second.
@@ -767,7 +766,7 @@ int install_firewall_perinterface(const char *ifbuf) {
     // grant it to rtapi_app.  Users who want full IPv6 quiescence (no
     // router solicitations etc.) can additionally set
     // 'net.ipv6.conf.<iface>.disable_ipv6=1' in /etc/sysctl.conf.
-    if(!use_firewall()) return 0;
+    if(!hm2_eth_use_firewall()) return 0;
 
     switch(fw_backend) {
     case FW_IPTABLES:
@@ -800,7 +799,7 @@ int install_firewall_perinterface(const char *ifbuf) {
     return 0;
 }
 
-int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
+int hm2_eth_fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
     lbp16_cmd_addr packet;
     unsigned char response[6];
     LBP16_INIT_PACKET4(packet, 0x4983, 0x0002);
@@ -1718,7 +1717,7 @@ int rtapi_app_main(void) {
         return ret;
     comp_id = ret;
 
-    clear_firewall();
+    hm2_eth_clear_firewall();
 
     for(i = 0, ret = 0; ret == 0 && i<MAX_ETH_BOARDS && board_ip[i] && *board_ip[i]; i++) {
         ret = init_board(&boards[i], board_ip[i], board_rtnet[i]);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index 5eae27bc85a..7363c1de27b 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -94,11 +94,10 @@ struct hm2_eth_t {
     } *hal;
 };
 
-bool use_firewall();
-int install_firewall_board(int sockfd);
-int install_firewall_perinterface(const char *ifbuf);
-void clear_firewall();
-char* fetch_ifname(int sockfd, char *buf, size_t n);
-int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]);
+bool hm2_eth_use_firewall();
+int hm2_eth_install_firewall_board(int sockfd);
+void hm2_eth_clear_firewall();
+char* hm2_eth_fetch_ifname(int sockfd, char *buf, size_t n);
+int hm2_eth_fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]);
 
 #endif
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index e90b84e1c6f..7c5d07bb5e3 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -72,7 +72,7 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
     }
 
     strncpy(board->ip, board_ip, sizeof(board->ip)-1);
-    char *ifptr = fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
+    char *ifptr = hm2_eth_fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
     if(!ifptr) {
         LL_PRINT("failed to retrieve interface name for board\n");
         return 0;
@@ -82,7 +82,7 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
         LL_PRINT("ERROR: can't SO_BINDTODEVICE socket: %s\n", strerror(errno));
     }
 
-    if (!use_firewall()) {
+    if (!hm2_eth_use_firewall()) {
         LL_PRINT(\
 "WARNING: Unable to restrict other access to the hm2-eth device.\n"
 "This means that other software using the same network interface can violate\n"
@@ -115,7 +115,7 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
 
     board->req.arp_ha.sa_family = AF_LOCAL;
     board->req.arp_flags = ATF_PERM | ATF_COM;
-    ret = fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
+    ret = hm2_eth_fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
     if (ret < 0) {
         LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
         return ret;
@@ -124,7 +124,7 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
     // install_firewall_board() is a no-op when no firewall backend is
     // available (rootless install without CAP_NET_ADMIN, or
     // firewall=none), so it is safe to call unconditionally.
-    ret = install_firewall_board(board->sockfd);
+    ret = hm2_eth_install_firewall_board(board->sockfd);
     if (ret < 0) return ret;
 
     board->write_packet_ptr = board->write_packet;
@@ -225,7 +225,7 @@ int hm2_evl_close_board(hm2_eth_t *board) {
 
     board->llio.reset(&board->llio);
 
-    clear_firewall();
+    hm2_eth_clear_firewall();
 
     ret = close(board->sockfd);
     if (ret == -1)
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index 0397536e058..5b20c121531 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -63,13 +63,13 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
     }
 
     strncpy(board->ip, board_ip, sizeof(board->ip)-1);
-    char *ifptr = fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
+    char *ifptr = hm2_eth_fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
     if(!ifptr) {
         LL_PRINT("failed to retrieve interface name for board\n");
         return 0;
     }
 
-    if(!use_firewall()) {
+    if(!hm2_eth_use_firewall()) {
         LL_PRINT(\
 "WARNING: Unable to restrict other access to the hm2-eth device.\n"
 "This means that other software using the same network interface can violate\n"
@@ -102,7 +102,7 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
 
     board->req.arp_ha.sa_family = AF_LOCAL;
     board->req.arp_flags = ATF_PERM | ATF_COM;
-    ret = fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
+    ret = hm2_eth_fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
     if(ret < 0) {
         LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
         return ret;
@@ -124,7 +124,7 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
     // install_firewall_board() is a no-op when no firewall backend is
     // available (rootless install without CAP_NET_ADMIN, or
     // firewall=none), so it is safe to call unconditionally.
-    ret = install_firewall_board(board->sockfd);
+    ret = hm2_eth_install_firewall_board(board->sockfd);
     if(ret < 0) return ret;
 
     board->write_packet_ptr = board->write_packet;
@@ -142,7 +142,7 @@ int hm2_posix_close_board(hm2_eth_t *board) {
     int ret;
     board->llio.reset(&board->llio);
 
-    clear_firewall();
+    hm2_eth_clear_firewall();
 
     if(board->req.arp_flags & ATF_PERM) {
         ret = ioctl(board->sockfd, SIOCDARP, &board->req);

From e9e27afe4db8163b4c00b7e4f1e5a67f4c1a60ad Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 14:04:27 +0200
Subject: [PATCH 3/7] hm2_eth: Add Xenomai3 support

---
 src/Makefile.inc.in                           |   1 +
 src/configure.ac                              |   4 +
 src/hal/drivers/Submakefile                   |  11 ++
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       |  71 ++++++++-
 .../mesa-hostmot2/hm2_eth_net_xenomai.c       | 143 ++++++++++++++++++
 .../mesa-hostmot2/hm2_eth_net_xenomai.h       |  34 +++++
 6 files changed, 257 insertions(+), 7 deletions(-)
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.h

diff --git a/src/Makefile.inc.in b/src/Makefile.inc.in
index c0ab1ceb631..c051cbb084f 100644
--- a/src/Makefile.inc.in
+++ b/src/Makefile.inc.in
@@ -235,6 +235,7 @@ RTAI_LXRT_LDFLAGS=@RTAI_LXRT_LDFLAGS@
 CONFIG_USPACE_XENOMAI=@CONFIG_USPACE_XENOMAI@
 XENOMAI_CFLAGS=@XENOMAI_CFLAGS@
 XENOMAI_LDFLAGS=@XENOMAI_LDFLAGS@
+XENOMAI_LDFLAGS_NOINIT=@XENOMAI_LDFLAGS_NOINIT@
 
 CONFIG_USPACE_XENOMAI_EVL=@CONFIG_USPACE_XENOMAI_EVL@
 XENOMAI_EVL_CFLAGS=@XENOMAI_EVL_CFLAGS@
diff --git a/src/configure.ac b/src/configure.ac
index 88d7959cd96..bb50b7c3550 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -242,17 +242,21 @@ if test "$RTS" = uspace || test -z "$RTS" -a "$RTAI_CONFIG" = "none" ; then
     CONFIG_USPACE_XENOMAI=n
     XENOMAI_CFLAGS=
     XENOMAI_LDFLAGS=
+    XENOMAI_LDFLAGS_NOINIT=
   else
     USPACE_XENOMAI=+xenomai
     CONFIG_USPACE_XENOMAI=y
     XENOMAI_CFLAGS=`$XENOMAI_CONFIG --skin posix --cflags`
     XENOMAI_LDFLAGS=`$XENOMAI_CONFIG --skin posix --ldflags`
+    #Libs need --no-auto-init, otherwhise, each module initialises xenomai at load
+    XENOMAI_LDFLAGS_NOINIT=`$XENOMAI_CONFIG --skin posix --ldflags --no-auto-init`
     AC_DEFINE([USPACE_XENOMAI], [], [Define if uspace realtime should optionally support Xenomai])
   fi
 
   AC_SUBST([CONFIG_USPACE_XENOMAI])
   AC_SUBST([XENOMAI_CFLAGS])
   AC_SUBST([XENOMAI_LDFLAGS])
+  AC_SUBST([XENOMAI_LDFLAGS_NOINIT])
 
   if test "$HAS_EVL" = "n" ; then
     USPACE_XENOMAI_EVL=
diff --git a/src/hal/drivers/Submakefile b/src/hal/drivers/Submakefile
index aab6f9dd3ac..516c9f33843 100644
--- a/src/hal/drivers/Submakefile
+++ b/src/hal/drivers/Submakefile
@@ -50,3 +50,14 @@ $(call TOOBJSDEPS, $(NET_EVL_SRCS)): EXTRAFLAGS += -fPIC $(XENOMAI_EVL_CFLAGS)
 TARGETS += ../lib/liblinuxcnc-hm2_eth_net_evl.so.0
 TARGETS += ../lib/liblinuxcnc-hm2_eth_net_evl.so
 endif
+
+ifeq ($(CONFIG_USPACE_XENOMAI),y)
+NET_XENOMAI_SRCS := hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
+USERSRCS += $(NET_XENOMAI_SRCS)
+$(call TOOBJSDEPS, $(NET_XENOMAI_SRCS)): EXTRAFLAGS += -fPIC $(XENOMAI_CFLAGS)
+../lib/liblinuxcnc-hm2_eth_net_xenomai.so.0: $(call TOOBJS, $(NET_XENOMAI_SRCS))
+	$(ECHO) Linking $(notdir $@)
+	$(Q)$(CXX) -shared $(LDFLAGS) -o $@ $^ $(XENOMAI_LDFLAGS_NOINIT) -Wl,-soname,$(notdir $@)
+TARGETS += ../lib/liblinuxcnc-hm2_eth_net_xenomai.so.0
+TARGETS += ../lib/liblinuxcnc-hm2_eth_net_xenomai.so
+endif
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index 43543766188..8ec9f6ab81d 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -45,7 +45,7 @@
 
 #include <hal.h>
 
-#include "config.h" //For USPACE_XENOMAI_EVL defines
+#include "config.h" //For USPACE_XENOMAI_EVL / USPACE_XENOMAI defines
 
 #include "hostmot2-lowlevel.h"
 #include "hostmot2.h"
@@ -834,6 +834,21 @@ static bool load_eth_net_evl(void) {
 }
 #endif
 
+#ifdef USPACE_XENOMAI_EVL
+static void *eth_net_xenomai_lib = NULL;
+static bool load_eth_net_xenomai(void) {
+    if (eth_net_xenomai_lib != NULL) {
+        return true; // Already checked
+    }
+    eth_net_xenomai_lib = dlopen("liblinuxcnc-hm2_eth_net_xenomai.so", RTLD_LOCAL | RTLD_NOW);
+    if (!eth_net_xenomai_lib) {
+        LL_PRINT("ERROR: XENOMAI support loading library failed: %s\n", dlerror());
+        return false;
+    }
+    return true;
+}
+#endif
+
 static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_rtnet){
     //Default (NULL) is posix
     if (board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0) {
@@ -842,6 +857,44 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
         board->close_board = &hm2_posix_close_board;
         board->eth_socket_send = &hm2_posix_eth_socket_send;
         board->eth_socket_recv = &hm2_posix_eth_socket_recv;
+    } else if (strcmp(board_rtnet, "xenomai") == 0) {
+#ifdef USPACE_XENOMAI
+        if (hal_get_realtime_type() != REALTIME_TYPE_XENOMAI) {
+            LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC not running with Xenomai realtime\n", board_rtnet)
+            return -1;
+        }
+        if (!load_eth_net_xenomai()) {
+            return -1;
+        }
+        board->init_board = dlsym(eth_net_xenomai_lib, "hm2_xenomai_init_board");
+        if (board->init_board == NULL) {
+            LL_PRINT("ERROR: XENOMAI support dlsym hm2_xenomai_init_board failed: %s\n", dlerror());
+            return -1;
+        }
+        board->init_board_realtime = dlsym(eth_net_xenomai_lib, "hm2_xenomai_init_board_realtime");
+        if (board->init_board_realtime == NULL) {
+            LL_PRINT("ERROR: XENOMAI support dlsym init_board_realtime failed: %s\n", dlerror());
+            return -1;
+        }
+        board->close_board = dlsym(eth_net_xenomai_lib, "hm2_xenomai_close_board");
+        if (board->close_board == NULL) {
+            LL_PRINT("ERROR: XENOMAI support dlsym hm2_xenomai_init_close_boardboard failed: %s\n", dlerror());
+            return -1;
+        }
+        board->eth_socket_send = dlsym(eth_net_xenomai_lib, "hm2_xenomai_eth_socket_send");
+        if (board->eth_socket_send == NULL) {
+            LL_PRINT("ERROR: XENOMAI support dlsym eth_socket_send failed: %s\n", dlerror());
+            return -1;
+        }
+        board->eth_socket_recv = dlsym(eth_net_xenomai_lib, "hm2_xenomai_eth_socket_recv");
+        if (board->eth_socket_recv == NULL) {
+            LL_PRINT("ERROR: XENOMAI support dlsym eth_socket_recv failed: %s\n", dlerror());
+            return -1;
+        }
+#else
+        LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC was built without Xenomai support\n", board_rtnet);
+        return -1;
+#endif
     } else if (strcmp(board_rtnet, "evl") == 0) {
 #ifdef USPACE_XENOMAI_EVL
         if (hal_get_realtime_type() != REALTIME_TYPE_XENOMAI_EVL) {
@@ -1746,12 +1799,16 @@ int rtapi_app_main(void) {
     for(i = 0; i<num_boards; i++) {
         boards[i].read_cnt = boards[i].write_cnt = 0;
         boards[i].has_written_cnt = 0;
-        int *added = kvlist_lookup(&ifnames, boards[i].ifname);
-        if(!added)
-            goto error;
-        if(*added) continue;
-        install_firewall_perinterface(boards[i].ifname);
-        *added = 1;
+        //Xenomai boards have an empty string for ifname due to the
+        //interface name can not be resolved and a firewall is not needed
+        if(strnlen(boards[i].ifname, sizeof(boards[i].ifname)) > 0){
+            int *added = kvlist_lookup(&ifnames, boards[i].ifname);
+            if(!added)
+                goto error;
+            if(*added) continue;
+            install_firewall_perinterface(boards[i].ifname);
+            *added = 1;
+        }
     }
 
     hal_export_functf(init_board_realtime_all, 0, 0, 0, comp_id, "%s.realtime-init", HM2_LLIO_NAME);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
new file mode 100644
index 00000000000..89d925ac092
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
@@ -0,0 +1,143 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    Xenomai Port:
+ *    Copyright 2026 Hannes Diethelm <hannes.diethelm@gmail.com>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if_arp.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <poll.h>
+
+#include <rtapi.h>
+#include <rtapi_string.h>
+
+#include "hostmot2-lowlevel.h"
+#include "hm2_eth_net_xenomai.h"
+
+#define SEND_TIMEOUT_US 10
+#define RECV_TIMEOUT_US 10
+
+/// ethernet io functions
+
+int hm2_xenomai_init_board(hm2_eth_t *board, const char *board_ip) {
+    int ret;
+    LL_PRINT("%s: INFO: init board (XENOMAI)\n", board_ip);
+    board->sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+    if (board->sockfd < 0) {
+        LL_PRINT("ERROR: can't open socket: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    //Check if socket is rtnet: F_GETFD will
+    //fail due to this is only supported on normal
+    //sockets. Nicer alternatives are welcome but
+    //it looks to be the only option.
+    //See: kernel/cobalt/rtdm/fd.c
+    if( fcntl(board->sockfd, F_GETFD) >= 0 ){
+        LL_PRINT("ERROR: Socket is not realtime\n"
+        "    Read hm2_eth man page how to enable realtime\n"
+        "    ethernet for Xenomai\n");
+        return -1;
+    }
+
+    board->server_addr.sin_family = AF_INET;
+    board->server_addr.sin_port = htons(LBP16_UDP_PORT);
+    board->server_addr.sin_addr.s_addr = inet_addr(board_ip);
+
+    board->local_addr.sin_family      = AF_INET;
+    board->local_addr.sin_addr.s_addr = INADDR_ANY;
+
+    ret = connect(board->sockfd, (struct sockaddr *) &board->server_addr, sizeof(struct sockaddr_in));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't connect: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    strncpy(board->ip, board_ip, sizeof(board->ip)-1);
+
+    memset(&board->req, 0, sizeof(board->req));
+    struct sockaddr_in *sin;
+
+    sin = (struct sockaddr_in *) &board->req.arp_pa;
+    sin->sin_family = AF_INET;
+    sin->sin_addr.s_addr = inet_addr(board_ip);
+
+    board->req.arp_ha.sa_family = AF_LOCAL;
+    board->req.arp_flags = ATF_PERM | ATF_COM;
+    ret = hm2_eth_fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
+    if(ret < 0) {
+        LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
+        return ret;
+    }
+
+    board->write_packet_ptr = board->write_packet;
+    board->read_packet_ptr = board->read_packet;
+
+    return 0;
+}
+
+int hm2_xenomai_init_board_realtime(hm2_eth_t *board){
+    (void)board;
+    return 0; //Nothing todo
+}
+
+int hm2_xenomai_close_board(hm2_eth_t *board) {
+    int ret;
+    board->llio.reset(&board->llio);
+
+    ret = close(board->sockfd);
+    if (ret == -1)
+        LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
+
+    return ret < 0 ? -errno : 0;
+}
+
+int hm2_xenomai_eth_socket_send(hm2_eth_t *board, const void *buffer, int len) {
+    return send(board->sockfd, buffer, len, 0);
+}
+
+int hm2_xenomai_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns) {
+    fd_set rfds;
+    struct timeval tv;
+    int ret;
+
+    //ppoll is not suported by xenomai, use select
+    FD_ZERO(&rfds);
+    FD_SET(board->sockfd, &rfds);
+    tv.tv_sec = 0;
+    tv.tv_usec = recv_timeout_ns;
+    ret = select(board->sockfd+1, &rfds, NULL, NULL, &tv);
+
+    if (ret < 0) {
+        LL_PRINT("ERROR: select() failed: %m\n");
+    } else if(ret) {
+        ret = recv(board->sockfd, buffer, len, 0);
+    } else {
+        errno = EAGAIN;
+        ret = -1;
+    }
+
+    return ret;
+}
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.h b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.h
new file mode 100644
index 00000000000..4fdd51ac17d
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.h
@@ -0,0 +1,34 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    Xenomai Port:
+ *    Copyright 2026 Hannes Diethelm <hannes.diethelm@gmail.com>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __INCLUDE_HM2_ETH_NET_XENOMAI_H
+#define __INCLUDE_HM2_ETH_NET_XENOMAI_H
+
+#include "hm2_eth.h"
+
+int hm2_xenomai_init_board(hm2_eth_t *board, const char *board_ip);
+int hm2_xenomai_init_board_realtime(hm2_eth_t *board);
+int hm2_xenomai_close_board(hm2_eth_t *board);
+int hm2_xenomai_eth_socket_send(hm2_eth_t *board, const void *buffer, int len);
+int hm2_xenomai_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns);
+
+#endif

From c2782e708fceebcda9615a772e485ba366162502 Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 15:40:13 +0200
Subject: [PATCH 4/7] hm2_eth: Reorder code so there is no need to export
 firewall functions

---
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 41 +++++++++++++------
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       |  7 +---
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   | 16 +-------
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.c | 16 +-------
 .../mesa-hostmot2/hm2_eth_net_xenomai.c       |  3 +-
 5 files changed, 35 insertions(+), 48 deletions(-)

diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index 8ec9f6ab81d..e406f4aa82c 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -52,9 +52,6 @@
 #include "hm2_eth.h"
 #include "hm2_eth_net_posix.h"
 
-EXPORT_SYMBOL(hm2_eth_use_firewall);
-EXPORT_SYMBOL(hm2_eth_install_firewall_board);
-EXPORT_SYMBOL(hm2_eth_clear_firewall);
 EXPORT_SYMBOL(hm2_eth_fetch_ifname);
 EXPORT_SYMBOL(hm2_eth_fetch_hwaddr);
 
@@ -595,7 +592,7 @@ static fw_state_t fw_state = FW_UNRESOLVED;
 // Resolve and bring up the firewall backend on first call, caching the
 // result.  Returns true when a backend is ready, false when isolation
 // is unavailable or disabled.
-bool hm2_eth_use_firewall() {
+static bool use_firewall() {
     if(fw_state != FW_UNRESOLVED)
         return fw_state == FW_READY;
 
@@ -642,8 +639,8 @@ bool hm2_eth_use_firewall() {
 
 // Drop all rules from our chain/table but keep the chain in place, so a
 // fresh set can be installed on (re-)init.
-void hm2_eth_clear_firewall() {
-    if(!hm2_eth_use_firewall()) return;
+static void clear_firewall() {
+    if(!use_firewall()) return;
     switch(fw_backend) {
     case FW_IPTABLES:
         IPT(1, "-F", CHAIN);
@@ -659,7 +656,7 @@ void hm2_eth_clear_firewall() {
 
 // Remove everything we installed: chain, OUTPUT jump, and (nft) table.
 static void cleanup_firewall() {
-    if(!hm2_eth_use_firewall()) return;
+    if(!use_firewall()) return;
     switch(fw_backend) {
     case FW_IPTABLES:
         IPT(1, "-F", CHAIN);
@@ -710,12 +707,12 @@ char* hm2_eth_fetch_ifname(int sockfd, char *buf, size_t n) {
     return NULL;
 }
 
-int hm2_eth_install_firewall_board(int sockfd) {
+static int install_firewall_board(int sockfd) {
     struct sockaddr_in srcaddr, dstaddr;
     char srchost[16], dsthost[16]; // enough for 255.255.255.255\0
     char dport_s[8], sport_s[8];
 
-    if(!hm2_eth_use_firewall()) return 0;
+    if(!use_firewall()) return 0;
 
     socklen_t addrlen = sizeof(srcaddr);
     int res = getsockname(sockfd, &srcaddr, &addrlen);
@@ -766,7 +763,7 @@ static int install_firewall_perinterface(const char *ifbuf) {
     // grant it to rtapi_app.  Users who want full IPv6 quiescence (no
     // router solicitations etc.) can additionally set
     // 'net.ipv6.conf.<iface>.disable_ipv6=1' in /etc/sysctl.conf.
-    if(!hm2_eth_use_firewall()) return 0;
+    if(!use_firewall()) return 0;
 
     switch(fw_backend) {
     case FW_IPTABLES:
@@ -938,7 +935,25 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
         return -1;
     }
 
-    return board->init_board(board, board_ip);
+    int ret;
+    ret = board->init_board(board, board_ip);
+    if (ret < 0) return ret;
+
+    if(board->needs_firewall){
+        if(!use_firewall()) {
+            LL_PRINT(\
+                "WARNING: Unable to restrict other access to the hm2-eth device.\n"
+                "This means that other software using the same network interface can violate\n"
+                "realtime guarantees.  See hm2_eth(9) for more information.\n");
+        }
+        // install_firewall_board() is a no-op when no firewall backend is
+        // available (rootless install without CAP_NET_ADMIN, or
+        // firewall=none), so it is safe to call unconditionally.
+        ret = install_firewall_board(board->sockfd);
+        if(ret < 0) return ret;
+    }
+
+    return 0;
 }
 
 /// ethernet io functions mapping
@@ -1770,7 +1785,7 @@ int rtapi_app_main(void) {
         return ret;
     comp_id = ret;
 
-    hm2_eth_clear_firewall();
+    clear_firewall();
 
     for(i = 0, ret = 0; ret == 0 && i<MAX_ETH_BOARDS && board_ip[i] && *board_ip[i]; i++) {
         ret = init_board(&boards[i], board_ip[i], board_rtnet[i]);
@@ -1820,6 +1835,7 @@ int rtapi_app_main(void) {
 error:
     for(i = 0; i<MAX_ETH_BOARDS && board_ip[i] && board_ip[i][0]; i++)
         close_board(&boards[i]);
+    clear_firewall();
     // Full teardown: rtapi_app_exit() is not called when rtapi_app_main()
     // fails, so this is the only chance to remove the chain and jump.
     cleanup_firewall();
@@ -1835,6 +1851,7 @@ void rtapi_app_exit(void) {
     for(i = 0; i<MAX_ETH_BOARDS && board_ip[i] && board_ip[i][0]; i++)
         close_board(&boards[i]);
 
+    clear_firewall();
     cleanup_firewall();
 
     kvlist_free(&board_num);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index 7363c1de27b..245e1e32e67 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -54,8 +54,8 @@ struct hm2_eth_t {
     int (*eth_socket_send)(hm2_eth_t *board, const void *buffer, int len);
     int (*eth_socket_recv)(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns);
 
-    //Only for evl implementation
-    bool is_evl_oob_active;
+    bool needs_firewall;    //Not all rt implementations need firewall
+    bool is_evl_oob_active; //For evl implementation: oob network active
 
     rtapi_u8 read_packet[1400];
     rtapi_u8 *read_packet_ptr;
@@ -94,9 +94,6 @@ struct hm2_eth_t {
     } *hal;
 };
 
-bool hm2_eth_use_firewall();
-int hm2_eth_install_firewall_board(int sockfd);
-void hm2_eth_clear_firewall();
 char* hm2_eth_fetch_ifname(int sockfd, char *buf, size_t n);
 int hm2_eth_fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]);
 
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index 7c5d07bb5e3..7b0abbaefe8 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -82,13 +82,6 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
         LL_PRINT("ERROR: can't SO_BINDTODEVICE socket: %s\n", strerror(errno));
     }
 
-    if (!hm2_eth_use_firewall()) {
-        LL_PRINT(\
-"WARNING: Unable to restrict other access to the hm2-eth device.\n"
-"This means that other software using the same network interface can violate\n"
-"realtime guarantees.  See hm2_eth(9) for more information.\n");
-    }
-
     struct timeval timeout;
     timeout.tv_sec = 0;
     timeout.tv_usec = RECV_TIMEOUT_US;
@@ -121,14 +114,9 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
         return ret;
     }
 
-    // install_firewall_board() is a no-op when no firewall backend is
-    // available (rootless install without CAP_NET_ADMIN, or
-    // firewall=none), so it is safe to call unconditionally.
-    ret = hm2_eth_install_firewall_board(board->sockfd);
-    if (ret < 0) return ret;
-
     board->write_packet_ptr = board->write_packet;
     board->read_packet_ptr = board->read_packet;
+    board->needs_firewall = true;
 
     return 0;
 }
@@ -225,8 +213,6 @@ int hm2_evl_close_board(hm2_eth_t *board) {
 
     board->llio.reset(&board->llio);
 
-    hm2_eth_clear_firewall();
-
     ret = close(board->sockfd);
     if (ret == -1)
         LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index 5b20c121531..825785390ed 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -69,13 +69,6 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
         return 0;
     }
 
-    if(!hm2_eth_use_firewall()) {
-        LL_PRINT(\
-"WARNING: Unable to restrict other access to the hm2-eth device.\n"
-"This means that other software using the same network interface can violate\n"
-"realtime guarantees.  See hm2_eth(9) for more information.\n");
-    }
-
     struct timeval timeout;
     timeout.tv_sec = 0;
     timeout.tv_usec = RECV_TIMEOUT_US;
@@ -121,14 +114,9 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
         board->req.arp_flags &= ~ATF_PERM;
     }
 
-    // install_firewall_board() is a no-op when no firewall backend is
-    // available (rootless install without CAP_NET_ADMIN, or
-    // firewall=none), so it is safe to call unconditionally.
-    ret = hm2_eth_install_firewall_board(board->sockfd);
-    if(ret < 0) return ret;
-
     board->write_packet_ptr = board->write_packet;
     board->read_packet_ptr = board->read_packet;
+    board->needs_firewall = true;
 
     return 0;
 }
@@ -142,8 +130,6 @@ int hm2_posix_close_board(hm2_eth_t *board) {
     int ret;
     board->llio.reset(&board->llio);
 
-    hm2_eth_clear_firewall();
-
     if(board->req.arp_flags & ATF_PERM) {
         ret = ioctl(board->sockfd, SIOCDARP, &board->req);
         if(ret < 0) perror("ioctl SIOCDARP");
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
index 89d925ac092..6b7b0afa2de 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
@@ -94,7 +94,8 @@ int hm2_xenomai_init_board(hm2_eth_t *board, const char *board_ip) {
 
     board->write_packet_ptr = board->write_packet;
     board->read_packet_ptr = board->read_packet;
-
+    board->needs_firewall = false;
+    
     return 0;
 }
 

From 8c80cf1baf6b2a9a6cb0edcac931567846b1f988 Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 21:37:30 +0200
Subject: [PATCH 5/7] Temp Commit: Add up/down scripts for testing

---
 rtnet_down.sh |  6 ++++++
 rtnet_up.sh   | 15 +++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100755 rtnet_down.sh
 create mode 100755 rtnet_up.sh

diff --git a/rtnet_down.sh b/rtnet_down.sh
new file mode 100755
index 00000000000..3888bcd29d1
--- /dev/null
+++ b/rtnet_down.sh
@@ -0,0 +1,6 @@
+#! /bin/sh
+rtifconfig rteth0 down
+
+rmmod rt_igb
+modprobe igb
+ifup enp2s0f0
diff --git a/rtnet_up.sh b/rtnet_up.sh
new file mode 100755
index 00000000000..68f140aef44
--- /dev/null
+++ b/rtnet_up.sh
@@ -0,0 +1,15 @@
+#! /bin/sh
+ifdown enp2s0f0
+
+modprobe rt_loopback
+modprobe rtudp
+modprobe rtipv4
+rmmod igb
+rmmod rt_igb
+modprobe rt_igb
+rtifconfig rteth0 up 192.168.1.120 netmask 255.255.255.254
+sleep 1
+rtroute solicit 192.168.1.121 dev rteth0
+sleep 1
+rtping 192.168.1.121
+

From 5c54eb6eec0f6418d5ccd297a757ee10eb865a61 Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 21:37:39 +0200
Subject: [PATCH 6/7] hm2_eth: EVL: Simplify initialisation

By attaching rtapi_app also to the EVL core, no posix initialisation is
needed and all can me set up in rtapi_app_main().
---
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       |   1 -
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   | 169 +++++++-----------
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.c |   3 -
 src/rtapi/uspace_xenomai_evl.cc               |  12 +-
 4 files changed, 79 insertions(+), 106 deletions(-)

diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index 245e1e32e67..fd96cd035b5 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -55,7 +55,6 @@ struct hm2_eth_t {
     int (*eth_socket_recv)(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns);
 
     bool needs_firewall;    //Not all rt implementations need firewall
-    bool is_evl_oob_active; //For evl implementation: oob network active
 
     rtapi_u8 read_packet[1400];
     rtapi_u8 *read_packet_ptr;
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index 7b0abbaefe8..70b52892040 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -38,7 +38,6 @@
 
 #include "hostmot2-lowlevel.h"
 #include "hm2_eth_net_evl.h"
-#include "hm2_eth_net_posix.h"
 
 #define SEND_TIMEOUT_US 10
 #define RECV_TIMEOUT_US 10
@@ -51,7 +50,12 @@ static int oob_disable_port(hm2_eth_t *board);
 int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
     int ret;
     LL_PRINT("%s: INFO: init board (Xenomai EVL)\n", board_ip);
-    board->is_evl_oob_active = false;
+
+    if (evl_get_self() < 0) {
+        LL_PRINT("ERROR: hm2_eth evl mode: Process not attached to EVL core\n");
+        return -1;
+    }
+
     board->sockfd = socket(PF_INET, SOCK_DGRAM | SOCK_OOB, IPPROTO_IP);
     if (board->sockfd < 0) {
         LL_PRINT("ERROR: can't open socket: %s\n", strerror(errno));
@@ -82,6 +86,14 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
         LL_PRINT("ERROR: can't SO_BINDTODEVICE socket: %s\n", strerror(errno));
     }
 
+    //oob_enable_port needs: sockfd / server_addr / ip / ifname
+    //However, it must be called before the first ethernet
+    //communication in hm2_eth_fetch_hwaddr.
+    ret = oob_enable_port(board);
+    if (ret < 0) {
+        return ret;
+    }
+
     struct timeval timeout;
     timeout.tv_sec = 0;
     timeout.tv_usec = RECV_TIMEOUT_US;
@@ -122,17 +134,8 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
 }
 
 int hm2_evl_init_board_realtime(hm2_eth_t *board) {
-    static bool error_shown = false;
-    if (board->is_evl_oob_active ) {
-        if (!error_shown) {
-            LL_PRINT("ERROR: realtime-init called while realtime is allready initialized\n"
-                     "    You might be you using \"addf hm2_eth.realtime-init servo-thread\"\n"
-                     "    instead of \"initf hm2_eth.realtime-init servo-thread\"\n");
-            error_shown = true;
-        }
-        return 0; //No failure in this case
-    }
-    return oob_enable_port(board);
+    (void)board;
+    return 0; //Nothing todo
 }
 
 static int oob_enable_port(hm2_eth_t *board) {
@@ -172,8 +175,6 @@ static int oob_enable_port(hm2_eth_t *board) {
     /*t2 = rtapi_get_time();
     LL_PRINT("Enable dur = %lli\n", t2-t1);*/
 
-    board->is_evl_oob_active=true;
-
     return 0;
 }
 
@@ -202,17 +203,18 @@ static int oob_disable_port(hm2_eth_t *board) {
 
     setfsuid(previous);
 
-    board->is_evl_oob_active=false;
-
     return 0;
 }
 
 int hm2_evl_close_board(hm2_eth_t *board) {
     int ret;
-    oob_disable_port(board);
 
     board->llio.reset(&board->llio);
 
+    //oob_disable_port must be called after the last
+    //ethernet communication
+    oob_disable_port(board);
+
     ret = close(board->sockfd);
     if (ret == -1)
         LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
@@ -231,99 +233,64 @@ static void print_addr(char* desc, struct sockaddr_in *addr){
 }
 */
 
-static int check_evl(hm2_eth_t *board) {
-    static bool error_shown = false;
-    if (!board->is_evl_oob_active && evl_get_self() >= 0) {
-        if (!error_shown) {
-            LL_PRINT("ERROR: hm2_eth evl mode: OOB not active in realtime thread\n"
-                     "    Please add: \"initf hm2_eth.realtime-init servo-thread\"\n"
-                     "    to your hal file\n");
-            error_shown = true;
-        }
-        return -1;
-    } else {
-        return 0;
-    }
-}
-
 int hm2_evl_eth_socket_send(hm2_eth_t *board, const void *buffer, int len) {
     ssize_t ret = 0;
-    ret = check_evl(board);
-    if (ret < 0) {
-        return ret;
+    struct iovec iov;
+    struct oob_msghdr msghdr;
+    struct timespec ts_timeout;
+
+    evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
+    ts_timeout.tv_nsec += 1000*SEND_TIMEOUT_US;
+    while (ts_timeout.tv_nsec >= 1e9) {
+        ts_timeout.tv_nsec -= 1e9;
+        ts_timeout.tv_sec ++;
     }
-    if (board->is_evl_oob_active) {
-        struct iovec iov;
-        struct oob_msghdr msghdr;
-        struct timespec ts_timeout;
-
-        evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
-        ts_timeout.tv_nsec += 1000*SEND_TIMEOUT_US;
-        while (ts_timeout.tv_nsec >= 1e9) {
-            ts_timeout.tv_nsec -= 1e9;
-            ts_timeout.tv_sec ++;
-        }
-
-        /* OUTPUT */
-        iov.iov_base = (void *)buffer;
-        iov.iov_len = len;
-        msghdr.msg_iov = &iov;
-        msghdr.msg_iovlen = 1;
-        msghdr.msg_control = NULL;
-        msghdr.msg_controllen = 0;
-        msghdr.msg_name = &board->server_addr;
-        msghdr.msg_namelen = sizeof(board->server_addr);
-        /*msghdr.msg_name = NULL;
-        msghdr.msg_namelen = 0;*/
-        msghdr.msg_flags = 0;
-        ret = oob_sendmsg(board->sockfd, &msghdr, &ts_timeout, 0);
-        if (ret == -1) {
-            LL_PRINT("ERROR: oob_sendmsg %m %i %li\n", errno, ret);
-        }
-    } else {
-        //While initialisation, use posix mode due
-        //to we are not in an evl thread
-        ret = hm2_posix_eth_socket_send(board, buffer, len);
+
+    /* OUTPUT */
+    iov.iov_base = (void *)buffer;
+    iov.iov_len = len;
+    msghdr.msg_iov = &iov;
+    msghdr.msg_iovlen = 1;
+    msghdr.msg_control = NULL;
+    msghdr.msg_controllen = 0;
+    msghdr.msg_name = &board->server_addr;
+    msghdr.msg_namelen = sizeof(board->server_addr);
+    /*msghdr.msg_name = NULL;
+    msghdr.msg_namelen = 0;*/
+    msghdr.msg_flags = 0;
+    ret = oob_sendmsg(board->sockfd, &msghdr, &ts_timeout, 0);
+    if (ret == -1) {
+        LL_PRINT("ERROR: oob_sendmsg %m %i %li\n", errno, ret);
     }
     return ret;
 }
 
 int hm2_evl_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns) {
     ssize_t ret = 0;
-    ret = check_evl(board);
-    if (ret < 0) {
-        return ret;
-    }
-    if (board->is_evl_oob_active) {
-        struct oob_msghdr msghdr;
-        struct iovec iov;
-        struct timespec ts_timeout;
-
-        evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
-        ts_timeout.tv_nsec += recv_timeout_ns;
-        while (ts_timeout.tv_nsec >= 1e9) {
-            ts_timeout.tv_nsec -= 1e9;
-            ts_timeout.tv_sec ++;
-        }
-
-        /* INPUT */
-        iov.iov_base = buffer;
-        iov.iov_len = len;
-        msghdr.msg_iov = &iov;
-        msghdr.msg_iovlen = 1;
-        msghdr.msg_control = NULL;
-        msghdr.msg_controllen = 0;
-        msghdr.msg_name = &board->local_addr;
-        msghdr.msg_namelen = sizeof(board->local_addr);
-        /*msghdr.msg_name = NULL;
-        msghdr.msg_namelen = 0;*/
-        msghdr.msg_flags = 0;
-        ret = oob_recvmsg(board->sockfd, &msghdr, &ts_timeout, 0);
-    } else {
-        //While initialisation, use posix mode due
-        //to we are not in an evl thread
-        ret = hm2_posix_eth_socket_recv(board, buffer, len, recv_timeout_ns);
+    struct oob_msghdr msghdr;
+    struct iovec iov;
+    struct timespec ts_timeout;
+
+    evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
+    ts_timeout.tv_nsec += recv_timeout_ns;
+    while (ts_timeout.tv_nsec >= 1e9) {
+        ts_timeout.tv_nsec -= 1e9;
+        ts_timeout.tv_sec ++;
     }
+
+    /* INPUT */
+    iov.iov_base = buffer;
+    iov.iov_len = len;
+    msghdr.msg_iov = &iov;
+    msghdr.msg_iovlen = 1;
+    msghdr.msg_control = NULL;
+    msghdr.msg_controllen = 0;
+    msghdr.msg_name = &board->local_addr;
+    msghdr.msg_namelen = sizeof(board->local_addr);
+    /*msghdr.msg_name = NULL;
+    msghdr.msg_namelen = 0;*/
+    msghdr.msg_flags = 0;
+    ret = oob_recvmsg(board->sockfd, &msghdr, &ts_timeout, 0);
     return ret;
 }
 
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index 825785390ed..3a196ca0e96 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -35,9 +35,6 @@
 #define SEND_TIMEOUT_US 10
 #define RECV_TIMEOUT_US 10
 
-EXPORT_SYMBOL(hm2_posix_eth_socket_send);
-EXPORT_SYMBOL(hm2_posix_eth_socket_recv);
-
 /// ethernet io functions
 
 int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
diff --git a/src/rtapi/uspace_xenomai_evl.cc b/src/rtapi/uspace_xenomai_evl.cc
index 84f997900fa..d50b17d97b9 100644
--- a/src/rtapi/uspace_xenomai_evl.cc
+++ b/src/rtapi/uspace_xenomai_evl.cc
@@ -49,6 +49,16 @@ struct EvlTask : RtapiTask {
 struct EvlApp : RtapiApp {
     EvlApp() : RtapiApp(SCHED_FIFO) {
         pthread_once(&key_once, init_key);
+         WithRoot r;
+        /* Attach to the EVL core for rtapi_app, so modules can use EVL core
+         * functions also in rtapi_app_main. This has no influence on realtime
+         * due to rtapi_app will run with SCHED_WEAK.
+         */
+        int tfd = evl_attach_self("linuxcnc-rtapi_app:%d", gettid());
+        if (tfd < 0) {
+            rtapi_print("evl_attach_self() failed ret %i errno %i\n", tfd, errno);
+            throw std::invalid_argument("evl_attach_self() failed");
+        }
     }
 
     RtapiTask *do_task_new() {
@@ -120,7 +130,7 @@ struct EvlApp : RtapiApp {
         {
             WithRoot r;
             /* Attach to the core. */
-            int tfd = evl_attach_self("linuxcnc-thread:%d", gettid());
+            int tfd = evl_attach_self("linuxcnc-realtime:%d", gettid());
             if (tfd < 0) {
                 rtapi_print("evl_attach_self() failed ret %i errno %i\n", tfd, errno);
                 return nullptr;

From e023330aa94fce9c2bb9e408c03e8da57f45244e Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Wed, 2 Sep 2026 21:37:46 +0200
Subject: [PATCH 7/7] hm2_eth: Deprecate realtime-init

This is not needed any more.
---
 docs/src/man/man9/hm2_eth.9.adoc              | 10 ----------
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 20 +------------------
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       |  1 -
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   |  5 -----
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.c |  5 -----
 .../mesa-hostmot2/hm2_eth_net_xenomai.c       |  5 -----
 6 files changed, 1 insertion(+), 45 deletions(-)

diff --git a/docs/src/man/man9/hm2_eth.9.adoc b/docs/src/man/man9/hm2_eth.9.adoc
index 0e6e3b43dcf..8197a7508ab 100644
--- a/docs/src/man/man9/hm2_eth.9.adoc
+++ b/docs/src/man/man9/hm2_eth.9.adoc
@@ -156,16 +156,6 @@ hm2___<BoardType>__.__<BoardNum>__.packet-read-timeout (s32, rw)::
 Setting this value too low can cause spurious read errors.
 Setting it too high can cause realtime delay errors.
 
-== FUNCTIONS
-
-hm2_eth.realtime-init::
-  Realtime initialization function. This function initializes the realtime
-  ethernet for *evl*. With *posix*, this function is not needed.
-  It needs to be called once at startup using:
-....
-initf hm2_eth.realtime-init servo-thread
-....
-
 == NOTES
 
 hm2_eth installs firewall rules to control the network interface while
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index e406f4aa82c..07875811b8e 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -850,7 +850,6 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
     //Default (NULL) is posix
     if (board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0) {
         board->init_board = &hm2_posix_init_board;
-        board->init_board_realtime = &hm2_posix_init_board_realtime;
         board->close_board = &hm2_posix_close_board;
         board->eth_socket_send = &hm2_posix_eth_socket_send;
         board->eth_socket_recv = &hm2_posix_eth_socket_recv;
@@ -868,11 +867,6 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
             LL_PRINT("ERROR: XENOMAI support dlsym hm2_xenomai_init_board failed: %s\n", dlerror());
             return -1;
         }
-        board->init_board_realtime = dlsym(eth_net_xenomai_lib, "hm2_xenomai_init_board_realtime");
-        if (board->init_board_realtime == NULL) {
-            LL_PRINT("ERROR: XENOMAI support dlsym init_board_realtime failed: %s\n", dlerror());
-            return -1;
-        }
         board->close_board = dlsym(eth_net_xenomai_lib, "hm2_xenomai_close_board");
         if (board->close_board == NULL) {
             LL_PRINT("ERROR: XENOMAI support dlsym hm2_xenomai_init_close_boardboard failed: %s\n", dlerror());
@@ -906,11 +900,6 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
             LL_PRINT("ERROR: EVL support dlsym hm2_evl_init_board failed: %s\n", dlerror());
             return -1;
         }
-        board->init_board_realtime = dlsym(eth_net_evl_lib, "hm2_evl_init_board_realtime");
-        if (board->init_board_realtime == NULL) {
-            LL_PRINT("ERROR: EVL support dlsym init_board_realtime failed: %s\n", dlerror());
-            return -1;
-        }
         board->close_board = dlsym(eth_net_evl_lib, "hm2_evl_close_board");
         if (board->close_board == NULL) {
             LL_PRINT("ERROR: EVL support dlsym hm2_evl_init_close_boardboard failed: %s\n", dlerror());
@@ -958,10 +947,6 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
 
 /// ethernet io functions mapping
 
-static inline int init_board_realtime(hm2_eth_t *board){
-    return board->init_board_realtime(board);
-}
-
 static inline int close_board(hm2_eth_t *board){
     return board->close_board(board);
 }
@@ -1766,10 +1751,7 @@ static int hm2_eth_items(hm2_eth_t *board) {
 void init_board_realtime_all(void *arg, long period){
     (void)arg;
     (void)period;
-    int i;
-    for(i = 0; i < boards_count; i++) {
-        init_board_realtime(&boards[i]);
-    }
+    LL_PRINT("DEPRECATED: \"initf hm2_eth.realtime-init\" is not needed and will be removed\n");
 }
 
 int rtapi_app_main(void) {
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index fd96cd035b5..871d1ed5fad 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -49,7 +49,6 @@ struct hm2_eth_t {
 
     //RT network specific functions
     int (*init_board)(hm2_eth_t *board, const char *board_ip);
-    int (*init_board_realtime)(hm2_eth_t *board);
     int (*close_board)(hm2_eth_t *board);
     int (*eth_socket_send)(hm2_eth_t *board, const void *buffer, int len);
     int (*eth_socket_recv)(hm2_eth_t *board, void *buffer, int len, int recv_timeout_ns);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index 70b52892040..3cf5cbd3560 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -133,11 +133,6 @@ int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
     return 0;
 }
 
-int hm2_evl_init_board_realtime(hm2_eth_t *board) {
-    (void)board;
-    return 0; //Nothing todo
-}
-
 static int oob_enable_port(hm2_eth_t *board) {
     //long long t1, t2;
     int devfd, ret;
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index 3a196ca0e96..40221877668 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -118,11 +118,6 @@ int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
     return 0;
 }
 
-int hm2_posix_init_board_realtime(hm2_eth_t *board){
-    (void)board;
-    return 0; //Nothing todo
-}
-
 int hm2_posix_close_board(hm2_eth_t *board) {
     int ret;
     board->llio.reset(&board->llio);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
index 6b7b0afa2de..b9ce8708b9b 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_xenomai.c
@@ -99,11 +99,6 @@ int hm2_xenomai_init_board(hm2_eth_t *board, const char *board_ip) {
     return 0;
 }
 
-int hm2_xenomai_init_board_realtime(hm2_eth_t *board){
-    (void)board;
-    return 0; //Nothing todo
-}
-
 int hm2_xenomai_close_board(hm2_eth_t *board) {
     int ret;
     board->llio.reset(&board->llio);