In older devices the misc partition is only for boot commands to recovery.
In newer devices it also stores A/B current slot information and retry counts.
Since you can get to fastboot:
Code:
fastboot getvar all
fastboot getvar current-slot
You shouldn't see any _a or _b and current-slot will be undefined.
If this is ok, then you are single slot and misc is very simple.
To boot to regular system:
Code:
fastboot erase misc
fastboot reboot
To boot to recovery:
Code:
fastboot flash misc misc-rec
fastboot reboot
But if recovery is broken you could get stuck in broken recovery.
Just rename this file.