This is the most specific and promising fix for error (-75), as it directly addresses the battery health verification that can trigger this error.
: If your iPhone is jailbroken, this can be a direct cause of error 75, as jailbreaks modify system files that the update process needs to access. The most reliable way to remove a jailbreak is to connect your iPhone to iTunes or Finder and choose "Restore iPhone". This will erase your device and install the latest iOS version. 3utools error unable to restore idevice--75-
3uTools supports various iOS devices, including iPhones, iPads, and iPod touches, and is compatible with both Windows and macOS operating systems. This is the most specific and promising fix
If you have tried all the steps above on different computers and still encounter Error -75, the issue is likely hardware-related. This will erase your device and install the
Device hardware faults
Ensure that all background Apple mobile device support processes are completely closed inside your system task manager before restarting 3uTools.
Case B — Corrupt IPSW: