Download iOS 9.0.1 (13A404) 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 9.0.1
Release Date 2015-09-23
Update Date 2015-09-19
Sha1sum
117c44cb1e6a737a4b0537864eb409e3d761a43f
Sha256sum
7221d1704ca22041eaac95e282f5252bbde80d64e6508199545fb092de30bacc
md5sum
ea985965ec30cbaa5a2a1538a8da6468
Size 1.47 GB
FileName
iPhone4,1_9.0.1_13A404_Restore.ipsw
Status

Download IPSW (1.47GB) Check device info
Release Notes

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

This update contains bug fixes including:

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

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

IPSW File Download FAQ