Originally Posted by jarves
So I just checked sammobile and they are already rolling out 4.3 updates on my S4 on my carrier. How do I revert back to 4.2 if I don't like the 4.3 update? Will NAND backup suffice? Will it backup everything from OS to apps and data?
I heard that knoxx will mess up the bootloader so it's hard to revert.
Please advise some techniques before I go on with the update.
The simple answer is... you can't!
Once you have updated to a Knox enabled firmware with a locked bootloader you cannot
revert back to a non Knox and unlocked bootloader firmware. Efforts to do so by using a nandroid backup have resulted in loss of sound and/or Wi-Fi among other things. Some attempts to change the PIT file have resulted in fried motherboards and bricked phones.
If you are rooted and on an unlocked firmware then you could try looking for a 4.3 ROM without Knox and the locked bootloader, which is what I am on.
See, Locked bootloader & Knox security on latest firmwares