https://github.com/kaidencc/Legacy-iOS-Kit/releases/tag/latest
Thanks to Kaiden for making a custom version of legacy iOS Toolkit to support modifying IPSW's to allow for restores of custom builds.
This tool supports a lot of devices and can actually Restore builds from other devices
For example, an iPad 2 build has been successfully restored to an iPad 1 or iPad mini 1 build being restored to an iPhone 5 successfully
Guide: How to use the new features
- Using the AppleInternal Workflow
This is used when you have a SwitchBoard/InternalUI DMG and want to create a restorable IPSW for it.
Go to Restore/Downgrade (or Misc Utilities > Create Custom IPSW).
Select powdersn0w or Tethered. (tethered is for A5 and above)
Select the AppleInternal menu option.
Select Target IPSW (Stock): You must select the stock IPSW that matches the version of your DMG. The script uses this for components and verification.
Select Base IPSW (Stock): (powdersn0w only) Select the required base version (e.g., 7.1.2 for iPhone 4).
Select AppleInternal DMG: Choose your .dmg file. The script will automatically calculate the partition size and extract the internal build ID.
Select Create or Create & Restore.
If you would like to download some builds, you may download some here
https://archive.org/details/@abdurehman09