About This Firmware
iOS 4.3.1
(build 8G4) is an official Apple IPSW
for the iPhone 3GS.
The download is 419.88 MB and is served directly from Apple's CDN.
This firmware is no longer signed by Apple. Standard downgrades are not possible, but the file remains available for reference and advanced use.
Verify the download using the checksums below.
Filename
iPhone2,1_4.3.1_8G4_Restore.ipsw
Checksums
SHA-256
4492b1a28b3e60ee2f230cb11eeae2fa9fea9ebfde26d600cc6425e1bcf3e609
SHA-1
6de986f2dbd16a65db122e7c54a70f31812d028a
MD5
694c93b5b608513136ba8956dff28ba7
Direct URL
https://secure-appldnld.apple.com/iPhone4/041-0549.20110325.ZxP8u/iPhone2,1_4.3.1_8G4_Restore.ipsw
Other Devices
iPhone XR
iPhone11,8
iPhone 6
iPhone7,2
iPhone 8 Plus (Global)
iPhone10,2
iPhone 15 Pro Max
iPhone16,2
iPhone 14 Pro Max
iPhone15,3
iPhone XS Max
iPhone11,6
How to Restore with This IPSW
iTunes / Finder
macOS & Windows- Download the .ipsw file to your computer.
- Connect your iPhone 3GS via USB.
- Open iTunes (Windows / macOS Mojave and earlier) or Finder (macOS Catalina+) and select your device.
- Update (keep data): hold Option (Mac) or Shift (Windows) and click Update, then pick the .ipsw file.
- Restore (erase & install): hold Option / Shift and click Restore iPhone…, then pick the .ipsw file.
- Wait for the process to finish - do not disconnect.
Restoring will erase all data on the device. Back up first.
3uTools
Windows- Download and install 3uTools from 3u.com.
- Connect your iPhone 3GS via USB and trust the computer on the device.
- Go to Flash & JB > Easy Flash.
- Click Import and select the downloaded .ipsw file.
- Choose Flash mode: Update keeps data, Restore wipes the device.
- Click Flash and wait for the progress bar to complete - do not disconnect.
Only flash firmware that matches your exact device model.
DFU Mode
Recovery tipIf your device is stuck in a boot loop or iTunes/Finder does not recognise it, enter DFU mode first, then select the .ipsw file as normal.
iPhone 8 / X and later
- Quickly press & release Volume Up
- Quickly press & release Volume Down
- Hold Side button until screen goes black
- Hold Side + Volume Down for 5 s
- Release Side, hold Volume Down 5 more s
- Black screen = DFU active
iPhone 7 / 7 Plus
- Hold Sleep/Wake + Volume Down for 8 s
- Release Sleep/Wake, keep holding Volume Down for 5 s
- Black screen = DFU active
iPhone 6s and earlier
- Hold Sleep/Wake + Home for 8 s
- Release Sleep/Wake, keep holding Home for 5 s
- Black screen = DFU active