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FIRMWARE DETAILS

iOS 17.5.1

Build: 21F90May 20, 2024Delta OTA
Stable

View details

Filename
4787e5d09e32c6abf70574d92844386d7cd7898f.zip
File size
2.04 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
2f259f2728410bbe9f20632c2d1108219bd0dfc83580923ad131b4d4d1ac3bc0
SHA-1
9dfe40d7967aaacd5aa492dc230448dabd6eb5ef
Required starting builds
21A340, 21A351
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)

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