FIRMWARE DETAILS

iOS 17.5.1

Build: 21F90May 20, 2024Delta OTA

Stable

View details

Filename: ca11a59954a0d9f71af4213716237f9682696e6c.zip
File size: 2.49 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: 70a035d2c72fdeeaebd29b1e32ace60cba34acadcdcdf34dbae4fca85cc0e79b
SHA-1: 573b0748344e75a03acace693b8cd68057ffee79
Required starting builds: 21A326, 21A327, 21A329, 21A360
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 15 iPhone15,4

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%3B21F90.json ↗

MIT — copyright 2022 emiyl
Last imported: Oct 19, 2026, 6:28 PM UTC
Record fingerprint: 1ae039bd01274135bfccfb7ce06a0234