IPSW · iOS
iOS 17.1 RC 2 IPSW Download (21B77)
Build 21B77, released October 20, 2023 — restore images for 4 iPhones, straight from Apple's servers.
Choose your iPhone
4 devices. Each row is one file on Apple's CDN.
iPhone15,4 8.02 GB
iPhone15,5 8.02 GB
iPhone16,1 8.21 GB
iPhone16,2 8.21 GBNo device matches.
21B77How to install iOS 17.1 RC 2 from the IPSW
Four steps, and the one that matters most is the first.
Back up first
A restore erases the device. Make an archived backup in Finder or the Apple Devices app — an iCloud backup taken on a newer version cannot be restored onto an older one. Our backup guide covers the difference.
Get the file for your exact model
Check Settings → General → About → Model Name, then download the IPSW for that device. The download shows the file size; compare it with the SHA-256 under Details if you want to be certain the file is intact.
Restore in Finder or Apple Devices
Connect with a cable, select the device, then hold Option (Mac) or Shift (Windows) and click Restore to choose the .ipsw. Update keeps your data but only works upward; Restore erases and is how you downgrade.
Set up or restore your backup
After the restore the device starts fresh. Restore the backup you made — only if it came from the same or an older version than the one you just installed.
Questions? Answers.
Can I restore iOS 17.1 RC 2 today?
Not at the moment — Apple has stopped signing 21B77, so a restore will be rejected at the final step. The files remain here for reference and for signed re-releases.
Which is the right file for my device?
Match the identifier in Settings → General → About (or under the model's name here) against the one on each row. Wi-Fi and Cellular iPads share a file; different generations never do. Restoring the wrong device's IPSW simply fails — it cannot damage the device.
What does "signed" mean?
Apple's servers must approve a firmware before a device will accept it, and Apple only approves the builds it is currently shipping. A signed file can be restored today; an unsigned one is rejected at the end of the process, however you obtained it. Signing status changes without notice, usually within days of a newer release, which is why this catalogue rechecks it automatically.
Will I lose my data?
A Restore erases the device — that is what makes a downgrade possible. An Update with an IPSW keeps your data, but only when moving to a newer version. Either way, make an archived backup on a computer first; an iCloud backup taken on a newer version will not restore onto an older one.