I just had the same thing happen. Have you found a solution?
> Current version: 0.6-210@210920
Ign:1 http://download.hiveos.farm/repo/binary InRelease
Ign:2 http://download2.hiveos.farm/repo/binary InRelease
Err:3 http://download.hiveos.farm/repo/binary Release
404 Not Found [IP: 104.22.10.47 80]
Err:4 http://download2.hiveos.farm/repo/binary Release
404 Not Found [IP: 51.15.211.112 80]
Reading package lists...
E: The repository 'http://download.hiveos.farm/repo/binary Release' no longer has a Release file.
E: The repository 'http://download2.hiveos.farm/repo/binary Release' no longer has a Release file.
Repository update failed
------------------------------------------------------
> Restarting autofan and watchdog
> Starting miners
Miner screen is already running
Run miner or screen -r to resume screen
Upgrade failed
That’s fair. I was a little concerned because my working rigs were updating just fine, but a new rig I assembled (with a newly flashed ssd) was running into this error. The flash image is pretty old so I was hoping that wasn’t the problem. I just ran the selfupgrade command today and everything went fine.