FIRMWARE DETAILS

iOS 17.2.1

Build: 21C66Dec 19, 2023Delta OTA

Stable

View details

Filename: 478ba24d6ab3fa36649a068042c0e54be8625147.zip
File size: 1.14 GB
File type: Delta OTA
Download host: updates.cdn-apple.com
Link availability: Not verified
Source reports active
Last link check: Not checked
SHA-256: 2374b85136406ef7e6f160f43718ad5a5afb3b53d6b837a0311098f468782e66
SHA-1: 2839f3ba7bd1f28e20d3ecfd8f794f3866949c62
Required starting builds: 21B101, 21B74, 21B91
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 (1)

iPhone SE (2nd generation) iPhone12,8

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