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FIRMWARE DETAILS

iOS 17.5.1

Build: 21F90May 20, 2024Delta OTA
Stable

View details

Filename
8bd2266b5dc887547df1543967924247d438caf8.zip
File size
3.71 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
66537266e4dde2ca5d6f4320b0466bf0a892506227e22ab655adf4cad9c16383
SHA-1
a3b208279002955494635d960f65fd460716d1b3
Required starting builds
20F66, 20F75
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