diff --git a/libraries/AP_HAL_ChibiOS/CANFDIface.cpp b/libraries/AP_HAL_ChibiOS/CANFDIface.cpp
index cc4001940a..4d57effbc9 100644
--- a/libraries/AP_HAL_ChibiOS/CANFDIface.cpp
+++ b/libraries/AP_HAL_ChibiOS/CANFDIface.cpp
@@ -379,6 +379,17 @@ int16_t CANIface::send(const AP_HAL::CANFrame& frame, uint64_t tx_deadline,
 
         if ((can_->TXFQS & FDCAN_TXFQS_TFQF) != 0) {
             stats.tx_overflow++;
+            if (stats.tx_success == 0) {
+                /*
+                  if we have never successfully transmitted a frame
+                  then we may be operating with just MAVCAN or UDP
+                  MCAST. Consider the frame sent if the send
+                  succeeds. This allows for UDP MCAST and MAVCAN to
+                  operate fully when the CAN bus has no cable plugged
+                  in
+                 */
+                return AP_HAL::CANIface::send(frame, tx_deadline, flags);
+            }
             return 0;    //we don't have free space
         }
         index = ((can_->TXFQS & FDCAN_TXFQS_TFQPI) >> FDCAN_TXFQS_TFQPI_Pos);
diff --git a/libraries/AP_HAL_ChibiOS/CanIface.cpp b/libraries/AP_HAL_ChibiOS/CanIface.cpp
index cd38315008..172e412b0e 100644
--- a/libraries/AP_HAL_ChibiOS/CanIface.cpp
+++ b/libraries/AP_HAL_ChibiOS/CanIface.cpp
@@ -325,6 +325,19 @@ int16_t CANIface::send(const AP_HAL::CANFrame& frame, uint64_t tx_deadline,
             txmailbox = 2;
         } else {
             PERF_STATS(stats.tx_overflow);
+#if !defined(HAL_BOOTLOADER_BUILD)
+            if (stats.tx_success == 0) {
+                /*
+                  if we have never successfully transmitted a frame
+                  then we may be operating with just MAVCAN or UDP
+                  MCAST. Consider the frame sent if the send
+                  succeeds. This allows for UDP MCAST and MAVCAN to
+                  operate fully when the CAN bus has no cable plugged
+                  in
+                 */
+                return AP_HAL::CANIface::send(frame, tx_deadline, flags);
+            }
+#endif
             return 0;       // No transmission for you.
         }