Apple iPhone 3GS iOS 4.2.1 IPSW firmware
Apple iPhone 3GS
Not signed
iOS 4.2.1
Build 8C148a For iPhone2,1, n88ap
Global · IPSW
A newer version is available for this region: iOS 6.1.6
Apple no longer signs this version, so a normal restore with Finder or iTunes will fail. Use a signed version unless you know you need this one.
Download
401 MB
Downloads from secure-appldnld.apple.com.
File details
- Device
- Apple iPhone 3GS
- OS
- iOS 4.2.1
- Region
- Global
- Type
- IPSW
- Released
- Size
- 401 MB
- File name
iPhone2,1_4.2.1_8C148a_Restore.ipsw- MD5
d688d2d48c8b054367adef8e7ab4f5ea- SHA-1
2787bb9fbf18594279d05682e6fd16d2b9612a2a- SHA-256
09f3617fcf3e419e12c4a3c62f1fe0ab3909d0573a00937584124f869a7df15d
After downloading, compare the checksum with the one above. If they differ, the file is incomplete — download it again.
Before you download
- Make sure your device’s model number is one of: iPhone2,1, n88ap. You will find it in Settings → About phone, or on the box.
- This file is for the Global region. Installing another region’s firmware can remove features or block updates.
- Apple devices can only restore versions marked “Signed”.
- Back up your photos, contacts and files first, and charge the battery above 50%.
How to install
Use Finder on a Mac or the Apple Devices app / iTunes on Windows to install an IPSW file. Apple only accepts versions it is still signing, so check the “Signed” label before you download.
Read the guide: How to restore an iPhone, iPad or iPod with an IPSW file