Download iOS 6.1.3 (10B329) for iPhone 4 (CDMA)

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 iPhone3,3
iOS Version 6.1.3
Release Date 1970-01-01
Update Date 2013-03-13
Sha1sum
42f09fdc2e35426cc402ee683efb3b5e62dfe46a
Sha256sum
987af91243af4c6fa89a125250ce4a2b2c7413e678e06431a11e3700273ab6e1
md5sum
db301240840daee619d98d87f6c89921
Size 0.87 GB
FileName
iPhone3,3_6.1.3_10B329_Restore.ipsw
Status

Download IPSW (0.87GB) Check device info
Release Notes

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

iOS 6.1.3

This update contains improvements and other bug fixes including:

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

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