Download iOS 15.2.1 (19C63) for iPhone 12 Pro Max

You will have to note that you can only restore signed IPSW firmware files using iTunes or 3utools.

❌ This IPSW firmware is not being Signed by Apple

Firmware Identifier iPhone13,4
iOS Version 15.2.1
Release Date 2022-01-12
Update Date 2022-01-08
Sha1sum
794697eda22e21c3c9cca4a57454c34007591b7d
Sha256sum
9cc298b014dd70075a1940d47561141e32a043cf20d3fd11fd3e154727bc24d0
md5sum
ec6793aeb3d0477e6751c70062a73a7f
Size 6.19 GB
FileName
iPhone13,4_15.2.1_19C63_Restore.ipsw
Status

Download IPSW (6.19GB) Check device info
Release Notes

It should be noted that these are the official release notes for the from Apple

iOS 15.2.1 contains bug fixes for your iPhone including:

For information on the security content of Apple software updates, please visit this website:

https://support.apple.com/kb/HT201222