Download iOS 9.3.5 (13G36) for iPhone 6s

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 iPhone8,1
iOS Version 9.3.5
Release Date 2016-08-25
Update Date 2016-08-20
Sha1sum
0f04c6e685a1ffc87b0bb3ff6bdf390b962cf95d
Sha256sum
e6c529effd8db789c78b67c2d05b0166f9ce980cfe07d2e7dc8ee275ead2605f
md5sum
24a1c634716759a405425ae5fd745dc4
Size 2.05 GB
FileName
iPhone8,1_9.3.5_13G36_Restore.ipsw
Status

Download IPSW (2.05GB) Check device info
Release Notes

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

iOS 9.3.5 provides an important security update for your iPhone or iPad and is recommended for all users.

For information on the security content of Apple software updates, please visit this website:

https://support.apple.com/kb/HT201222