Download MacOS 12.3.1 Build 21E258 IPSW Firmware Restore Files
Download the IPSW MacOS 12.3.1 (Build 21E258) firmware file released at 31 March 2022 intended to restore Mac Studio (M1 Ultra) via iTunes. IPSW MacOS 12.3.1 build 21E258 is signed by Apple to update Apple device software.