"This Device Isn't Eligible for the Requested Build": Causes and Fixes

You downloaded an IPSW, started the restore in Finder, Apple Devices or iTunes, and got the message "The iPhone could not be restored. This device isn't eligible for the requested build." This message comes from Apple's server: it refused to authorize the installation. Here is why.

Cause 1: the firmware is no longer signed (most common)

Each installation must be approved ("signed") by Apple for your device. A few days or weeks after a new version, Apple stops signing the older one. After that, installing it is impossible, even with a perfect IPSW file.

• Check with our Signing Status tool: if the version is shown as unsigned, this is the cause.
• Solution: download the latest signed version for your model.

Background: signed vs unsigned IPSW explained. This is also why going back to an old iOS is often impossible: can you downgrade iOS 27 to iOS 26?

Cause 2: the IPSW is for another model

An iPhone 16 Pro (iPhone17,1) needs a different file from an iPhone 16 Pro Max (iPhone17,2). Check your exact identifier:

To find your exact model, open Settings > General > About and tap Model Number once to reveal the A-number (for example A3090). Enter that A-number in our Identifier Lookup tool. Our guide how to find your iPhone model identifier explains each method.

Cause 3: a modified "hosts" file on the computer

Old jailbreak or downgrade tools sometimes added lines to the computer's hosts file that redirect gs.apple.com (Apple's signing server). Then every restore is refused.

• Windows: open Notepad as administrator, open C:\Windows\System32\drivers\etc\hosts, delete any line containing gs.apple.com, save.
• Mac: in Terminal, type sudo nano /etc/hosts, delete those lines, press Control-O then Control-X.

Cause 4: network, VPN or security software

A VPN, firewall, school or company network, or antivirus can block the connection to Apple. Try another network (for example your phone's hotspot) and disable the VPN during the restore. Also check the computer's date and time.

Cause 5: beta builds after their expiry

Beta builds are signed only for a short time. When a new beta or the final version comes out, the older beta is often refused. Download the current beta from our beta firmware page or the final version.

What does NOT work

• Renaming the file, trying another cable or another USB port will not change Apple's answer.
• Programs that promise to "install any iOS version" cannot bypass Apple's signing on modern iPhones. At best, they install the latest signed version, which you can do for free.

Step-by-step: restore the latest signed version

1. Download the IPSW for your model:

• iPhone 18 Pro · iPhone 18 Pro Max
• iPhone 17 · iPhone 17 Pro · iPhone 17 Pro Max · iPhone Air · iPhone 17e
• iPhone 16 · iPhone 16 Plus · iPhone 16 Pro · iPhone 16 Pro Max · iPhone 16e
• iPhone 15 · iPhone 15 Plus · iPhone 15 Pro · iPhone 15 Pro Max
• iPhone 14 · iPhone 14 Plus · iPhone 14 Pro · iPhone 14 Pro Max
• iPhone 13 mini · iPhone 13 · iPhone 13 Pro · iPhone 13 Pro Max
• iPhone 12 mini · iPhone 12 · iPhone 12 Pro · iPhone 12 Pro Max
• iPhone 11 · iPhone 11 Pro · iPhone 11 Pro Max
• iPhone SE (2nd gen) · iPhone SE (3rd gen)

Another model? Browse all iPhone firmware or use the Identifier Lookup tool.

2. Put the iPhone in recovery mode:

• iPhone 8 and later (including iPhone SE 2nd/3rd generation): press and release Volume Up, press and release Volume Down, then press and hold the Side button. Keep holding when the Apple logo appears and release only when you see the computer-and-cable recovery screen.
• iPhone 7 and 7 Plus: press and hold the Side (or Top) button and Volume Down together until the recovery screen appears.
• iPhone 6s and earlier, iPhone SE (1st generation): press and hold the Home button and the Side (or Top) button together until the recovery screen appears.

3. In Finder or Apple Devices, hold Option (Mac) or Shift (Windows) and click Restore, then choose the file.

Other errors: errors 4005, 9 and 14, errors 4013 and 4014.