The MacBook Pro (Mid 2012) won't boot because it can't find the system software (flashing questionmark folder when trying to boot). I tried to reinstall the system by installing macOS on an external HDD, booting the MacBook Pro from the HDD and trying to erase the internal HDD (APFS) which won't work because of the following error:
POSIX reports: The operation couldn't be completed. Input/output error.
I also tried to erase the internal HDD with diskutil apfs deleteContainer
/dev/disk2s2, same problem,
Error: 5: Input/output error
Trying to run First Aid gives the following error on the APFS Physical Storage:
The volume /dev/disk0s2 could not be verified completely.
Storage system check exit code is 8.
Storage system verify or repair failed.
Anything else I could try?