After updating my cube purple to rover 4.1.0 from 4.0.0 the sik radio mavlink became slow and unstable. Getting param gets stuck on mavftp and after 5mins or so it might get past that but the rest of the param takes forever. After about 15min the link gets disconnected and I can not reconnect unless I restart the FC. I read about the log_backend_typ so I tried setting it to 0 but that did not resolve the problem. Tried a few things like checking on and off the ecc, rts/cts but that didn’t help. Updating the sik radio firmware seemed like it worked but after a few connect/disconnect it was back to being slow. Went back to rover 4.0.0 and it is working fine. What changed from 4.0.0 to 4.1.0 that might be causing this?
If you confirm that upgrading from 4.0.0 to 4.1.0 causes the issue, you may go to Ardupilot forum to report the issue.