Are you sick and tired of that stupid ATT software update feature that does nothing for you in terms of upgrading you to latest software? I have discovered that you can flash the Cricket 6.0.1 to your AT&T S6 and get rid of a lot of bloatware that comes with the AT&T S6 in the process.  After you flash this, you will end up seeing a Cricket boot logo and sound instead of that awfully loud AT&T boot up sound.

Upgrade to latest 6.0.1 G920A Marshmallow S6 Odin Flash

If your phone is unlocked and not on the AT&T network–AT&T won’t allow you to update to latest version.  Cricket runs on the AT&T network so a Cricket S6 is no different than an AT&T S6 and they both have same hardware and bootloaders and all of that.

Just download latest version of Odin via this link

http://forum.xda-developers.com/showthread.php?t=2711451

and then just flash all of the files in this zip folder.  Make sure you select all the files like BL, AP CSC etc.

https://www.androidfilehost.com/?fid=24665542585483500

Flashing the Cricket 6.0.1 MarshMallow will upgrade your S6 G920A to latest 6.0.1 and you will enjoy all of the benefits of having the latest version.  Lots of great improvements and security.  Best part of it is that you don’t void your warranty at all, secured Bootloader allows flashing of this file.

And one final note–once you flash this you may see a never ending message error popup.  This error is due to AT&T message app overlapping with the newly flashed Cricket 6.0.1.  All you have to do is boot up to recovery and then wipe cache and factory data reset and you will be good to go.

Upgrade 6.0.1 S6