diff --git a/examples/companion_radio/main.cpp b/examples/companion_radio/main.cpp
index 89f0e6cb9f..cf30f9ad82 100644
--- a/examples/companion_radio/main.cpp
+++ b/examples/companion_radio/main.cpp
@@ -61,7 +61,13 @@ MultiSerialInterface interface_manager;
 #if defined(SERIAL_RX)
   #include <helpers/ArduinoSerialInterface.h>
   ArduinoSerialInterface hardware_serial_interface;
-  HardwareSerial companion_serial(1);
+  #if defined(NRF52_PLATFORM)
+    // nRF52 has no numbered-constructor HardwareSerial; Serial1 is the concrete UARTE0
+    // instance the core always defines. setPins() below moves it to the requested pads.
+    Uart& companion_serial = Serial1;
+  #else
+    HardwareSerial companion_serial(1);
+  #endif
 #endif
 
 // platform file system
diff --git a/variants/xiao_nrf52/platformio.ini b/variants/xiao_nrf52/platformio.ini
index 1076bd8de7..1eb216d15a 100644
--- a/variants/xiao_nrf52/platformio.ini
+++ b/variants/xiao_nrf52/platformio.ini
@@ -119,3 +119,28 @@ build_src_filter = ${Xiao_nrf52.build_src_filter}
   +<../examples/kiss_modem/*.cpp>
 lib_deps =
   ${Xiao_nrf52.lib_deps}
+
+[env:Xiao_nrf52_companion_radio_serial]
+extends = Xiao_nrf52
+board_build.ldscript = boards/nrf52840_s140_v7_extrafs.ld
+board_upload.maximum_size = 708608
+build_flags =
+  ${Xiao_nrf52.build_flags}
+  -I examples/companion_radio/ui-orig
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D OFFLINE_QUEUE_SIZE=256
+  -D QSPIFLASH=1
+  -D SERIAL_TX=D6
+  -D SERIAL_RX=D7
+  -D PIN_WIRE_SCL=16
+  -D PIN_WIRE_SDA=17
+build_unflags =
+  -D PIN_WIRE_SCL=D6
+  -D PIN_WIRE_SDA=D7
+build_src_filter = ${Xiao_nrf52.build_src_filter}
+  +<../examples/companion_radio/*.cpp>
+  +<../examples/companion_radio/ui-orig/*.cpp>
+lib_deps =
+  ${Xiao_nrf52.lib_deps}
+  densaugeo/base64 @ ~1.4.0