Note-first take a backup of your full rom
Download s322 file
Extract the zip in a separate folder using winrar archiver or any other extractor.
Go to meta-inf–com–google–android and delete updter-script.
Now download new updater-script
Put this updater-script exactly where you deleted it from.
Now compress all the files in the extracted folder into a zip file.
After your archive is compressed, move it to the external card.
Now go into twrp recovery, click wipe and then delete dalvik cache, and system partition userdata 1st
Now go to install the compressed zip file.
Wait for boot
Now you are upgraded to Android 6.
This method is totally safe.
don’t want to be on previous versions of stock rom, s121 or s205. Flash it like any other rom via twrp.
Credits #Viksandroid
(www.Viksandroid.blogspot.in)
