Download iOS 9.3.1 (13E238) for iPhone 4[S]

You will have to note that you can only restore signed IPSW firmware files using iTunes or 3utools.

❌ This IPSW firmware is not being Signed by Apple

Firmware Identifier iPhone4,1
iOS Version 9.3.1
Release Date 2016-03-31
Update Date 2016-03-30
Sha1sum
1699e0986e3746644fa16a8f370b0c4b42d8cf9a
Sha256sum
e3c68c5532e924374ed04bf16f71efa5e37bcff23d7bd8e9e4b01ccfb6ea0e3a
md5sum
009666885e7e19bcbf0137379abd56c0
Size 1.50 GB
FileName
iPhone4,1_9.3.1_13E238_Restore.ipsw
Status

Download IPSW (1.50GB) Check device info
Release Notes

It should be noted that these are the official release notes for the from Apple

Fixes an issue that caused apps to be unresponsive after tapping on links in Safari and other apps

For information on the security content of this update, please visit this website:

http://support.apple.com/kb/HT1222