OTBR add-on randomly stops

Configuration Matter/Thread
1

As the title says, everything works fine for a day or two, and then the OpenThread Border Router add-on simply stops. The Docker container exits, and the watchdog doesn’t seem to restart it.

Sometimes I see errors like this:

00:00:29.443 [W] P-RadioSpinel-: RCP failure detected
00:00:29.443 [C] P-RadioSpinel-: Too many rcp failures, exiting
00:00:29.443 [C] Platform------: RecoverFromRcpFailure() at radio_spinel.cpp:2063: Failure
[23:39:33] WARNING: motbr-agent exited with code 1 (by signal 0).

Other times, I get:

00:13:24.958 [W] P-RadioSpinel-: radio tx timeout
00:13:24.967 [C] P-RadioSpinel-: Failed to communicate with RCP - no response from RCP during initialization
00:13:24.967 [C] P-RadioSpinel-: This is not a bug and is typically due to a configuration error (wrong URL parameters) or a bad RCP image:
00:13:24.967 [C] P-RadioSpinel-: - Make sure RCP is running the correct firmware
00:13:24.967 [C] P-RadioSpinel-: - Double-check the config parameters passed as `RadioURL` input
00:13:24.967 [C] Platform------: HandleRcpTimeout() at radio_spinel.cpp:2013: RadioSpinelNoResponse
[09:30:17] WARNING: motbr-agent exited with code 6 (by signal 0).

If I manually start the add-on again, everything works normally.

Any ideas what could be causing this?

I’m using an SLZB-MR2 in dual mode, connected via PoE. Zigbee is completely stable, but Thread has this issue almost every day.

2

Hi!

I am getting the same error using a ZBT-2 (connected to a USB Cat extender) after a couple of days.

It seems that the ZBT-2 is hanging when this happens - I have to unplug and plug it in again.

Any help would be appreciated!

1d.02:10:43.659 [W] P-RadioSpinel-: radio tx timeout

1d.02:10:43.671 [C] P-RadioSpinel-: Failed to communicate with RCP - no response from RCP during initialization

1d.02:10:43.671 [C] P-RadioSpinel-: This is not a bug and typically due a config error (wrong URL parameters) or bad RCP image:

1d.02:10:43.671 [C] P-RadioSpinel-: - Make sure RCP is running the correct firmware

1d.02:10:43.671 [C] P-RadioSpinel-: - Double check the config parameters passed as RadioURL input

1d.02:10:43.671 [C] Platform------: HandleRcpTimeout() at radio_spinel.cpp:2013: RadioSpinelNoResponse

[09:53:41] WARNING: otbr-agent exited with code 6 (by signal 0).

3

Based on it working mostly and failing occasionally / randomly, I would look at hardware stability, specifically the USB Cat extender:

Either USB hub power drop or hub related issues. Plug it directly into host temporarily and try again and see if it stops

4

have similar issue every 10-20 days. I use SLZB-06 connected wia 0.5m USB 3.2 Gen 2 cable to my SBC.

2026-04-08 06:17:42.740 
 
otbr-agent exited with code 6 (by signal 0). 

2026-04-08 06:17:42.664 
 
07:37:41.459 [C] Platform------: HandleRcpTimeout() at radio_spinel.cpp:2013: RadioSpinelNoResponse 

2026-04-08 06:17:42.664 
 
07:37:41.459 [C] P-RadioSpinel-: - Double check the config parameters passed as `RadioURL` input 

2026-04-08 06:17:42.664 
 
07:37:41.459 [C] P-RadioSpinel-: - Make sure RCP is running the correct firmware 

2026-04-08 06:17:42.664 
error 
07:37:41.459 [C] P-RadioSpinel-: This is not a bug and typically due a config error (wrong URL parameters) or bad RCP image: 

2026-04-08 06:17:42.664 
 
07:37:41.459 [C] P-RadioSpinel-: Failed to communicate with RCP - no response from RCP during initialization