MacBook Pro (M1 Max, 16-inch, 2021) · MacBookPro18,2

MacBook Pro (M1 Max, 16-inch, 2021) · macOS 12.3.1

21E258Signed

Catalog data · Last updated: Oct 22, 2026, 10:32 PM UTC

Restore IPSW for MacBook Pro (M1 Max, 16-inch, 2021): macOS 12.3.1, build 21E258.

Firmware information

Version: macOS 12.3.1
Build: 21E258
IPSW: Mac restore IPSW, not a macOS installer
Size: 12.92 GB
Release date: Mar 31, 2022, 5:25 PM UTC
File name: UniversalMac_12.3.1_21E258_Restore.ipsw
Download host: updates.cdn-apple.com

IPSW download

Check the model and signing status before downloading.

Download IPSW

Download hostupdates.cdn-apple.comUniversalMac_12.3.1_21E258_Restore.ipsw

Back up before you restore. A restore can erase the data on the device. The identifier has to match, and a file you can download may still be rejected for restore. This is Mac restore firmware, not a regular macOS installer. The restore steps depend on the model.

Checksum

SHA-256cb0443525571ea5e54aa5a8fd9c52774591892311405183741f4a02f993e18d5

SHA-181033c922c5d43f57907d063fb01865f4c856b37

MD56c943a751207e9e06ab018a7bb568d40