diff --git a/supervisor/shared/usb/usb_msc_flash.c b/supervisor/shared/usb/usb_msc_flash.c
index 5ea457ef328cc..2ddf38939d3a0 100644
--- a/supervisor/shared/usb/usb_msc_flash.c
+++ b/supervisor/shared/usb/usb_msc_flash.c
@@ -214,8 +214,13 @@ int32_t tud_msc_scsi_cb(uint8_t lun, const uint8_t scsi_cmd[16], void *buffer, u
 
     switch (scsi_cmd[0]) {
         case SCSI_CMD_PREVENT_ALLOW_MEDIUM_REMOVAL:
-            // Host is about to read/write etc ... better not to disconnect disk
-            resplen = 0;
+            // All LUNs advertise is_removable=1 in INQUIRY (tinyusb default).
+            // Reply "unsupported" so the host keeps polling TUR and can
+            // re-mount after an eject. Responding OK tells the host to skip
+            // TUR polling, which breaks re-mount and can miss SD insertion
+            // events at boot. See adafruit/circuitpython#6555.
+            tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, 0x20, 0x00);
+            resplen = -1;
             break;
 
         default: