FIRMWARE DETAILS

iOS 17.2.1

Build: 21C66Dec 19, 2023Full OTA

Stable

View details

Filename: 387534500408f0c0867b48bef124a1e581b12ed0.zip
File size: 5.98 GB
File type: Full OTA
Download host: updates.cdn-apple.com
Link availability: Not verified
Source reports active
Last link check: Not checked
SHA-256: 660e6924bc56fa46ef5ef1e1dbfcc808e79595934809123e19d19179d8fc3260
SHA-1: 67af066e7cb5e9548ec57d6eff295c20df1758b6
Required starting builds: Not reported
Board restrictions: Not reported

OTA packages can require an exact starting build and board. A matching hardware identifier alone is not sufficient for installation.

Compatible hardware (3)

iPhone XS iPhone11,2

Unknown

iPhone XS Max iPhone11,6

Unknown

iPhone XS Max (China mainland) iPhone11,4

Unknown

Signing is specific to the device and file. A signed build does not guarantee a downgrade or successful installation.

Source provenance

AppleDBhttps://api.appledb.dev/ios/iOS%3B21C66.json ↗

MIT — copyright 2022 emiyl
Last imported: Oct 19, 2026, 6:28 PM UTC
Record fingerprint: d446c7f095cdf40f999162af3ba1751c