The system cannot mount the APFS data volume, often requiring a full erase rather than a simple update.

reg delete "HKLM\SYSTEM\CurrentControlSet\Enum\USB\VID_05AC&PID_12A8" /f reg delete "HKLM\SYSTEM\CurrentControlSet\Enum\USB\VID_05AC&PID_1281" /f

. It can also stem from power delivery issues or degraded battery health. Apple Support Community Primary Fixes for Error 75 Use Quick Flash with "Fix Battery Health" Open 3uTools and go to the Smart Flash Select the Quick Flash Mode (note: this will erase data). Check the box for "Fix battery health"

Sometimes your security software mistakes the firmware download or the restoration handshake for a threat.