About This Firmware
iOS 4.2.1
(build 8C148) is an official Apple IPSW
for the iPhone 3G.
The download is 322.89 MB and is served directly from Apple's CDN.
This firmware is currently signed by Apple, so it can be used to restore or update your device via iTunes or Finder.
Verify the download using the checksums below.
Filename
iPhone1,2_4.2.1_8C148_Restore.ipsw
Checksums
SHA-256
98e5969c3baed660c9a26e94cd7ed4b3cdb7175900f448bcc2223bf885835ce0
SHA-1
d2ed58586e8ca2153f2e2ec585bba8afc5173378
MD5
8b1657935408a1638b69740b282f62b3
Direct URL
https://secure-appldnld.apple.com/iPhone4/061-9853.20101122.Vfgt5/iPhone1,2_4.2.1_8C148_Restore.ipsw
Other Devices
iPhone SE
iPhone8,4
iPhone 17 Pro
iPhone18,1
iPhone 7 (Global)
iPhone9,1
iPhone 17e
iPhone18,5
iPhone XR
iPhone11,8
iPhone 12
iPhone13,2
How to Restore with This IPSW
iTunes / Finder
macOS & Windows- Download the .ipsw file to your computer.
- Connect your iPhone 3G 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 3G 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