Modifying an IPSW file is the digital equivalent of performing open-heart surgery on your iPhone. It is the gateway to jailbreaking, custom root filesystems, and legacy OS restoration. However, it is also a minefield of security protocols, cryptographic signatures, and bricked devices.
You need specific AES keys to decrypt the DMG files inside the IPSW. Sites like The iPhone Wiki maintain a database of these keys. modify ipsw file
After you've made the necessary changes, you'll need to repackage the IPSW file using the ipsw command-line tool. Modifying an IPSW file is the digital equivalent
: Smaller disk images used during the restore and update process. Bootloaders custom root filesystems