My personal full wipe instructions.
Follow at own risk, what works for me doesnt mean it will for you.
If your base is 5.1.1.
Reboot into download mode (power off phone, hold volume down, home and power until device shows blue screen, press up.)
Connect to computer running latest samsung usb drivers.
Open odin and select latest AP and select twrp file found on page one.
Reboot phone recovery (power off, hold volume up, home button and power button until screen lights up, release hold hold again until twrp logo and release)
Goto backup and select all check boxes!! MAKE SURE EFS/MODEM ARE SELECTED.
swipe and backup.
Reboot phone and connect to computer in disk mode. Make a copy of twrp backup folder on your pc.
Goto
http://forum.xda-developers.com/gal...t/g925f-android-marshmallow-6-0-beta-t3293964
And download the rom file and the deodexed patch. Copy to internalstorage "roms"(make yourself) directory.
And from this thred download the 6.0.1 and extract/copy to internalstorage/twrp/backups/devicenumber/6.0.1
Download sboot and supersu and copy to internal storage "roms" (make yourself)
Reboot to twrp.
Make another backup to be sure.
Install zip and navigate to roms and install 6.0 beta downloaded from other thred. Then install patch zip.
Then clear cache and dalvik.
Goto main twrp menu, select reboot then reboot to download mode.
In odin select BL and select
BOOTLOADER_G925FXXU3ZOL6-M(6.0).tar
From other forum. Flash and allow to reboot. (Will take 10 mins).
Once booted. Power off and boot into download mode.
Open odin and select BL and then the 5.1.1 bootloader.
Select AP and twrp
Flash.
Reboot into twrp. Goto wipe and select only system and data. Then wipe.
Goto restore and restore 6.0.1 backup. When done wipe dalvik and cache but dont reboot.
Now flash super su. And xposed (79.1 sdk 23 adm64) if you wish. Wipe dalvik and cache again.
Goto main twrp menu and reboot to download mode.
Open odin and select BL and flash sboot.
Reboot and hope.
Most steps are overboard but i found this to work with no hiccups. 6.0 probably isnt needed but doesnt hurt.