My goal is really to upgrade to KitKat while preserving root, and I read through the upgrade script.
My question whether I need to backup anything to allow me to return (reFlash) back to my JB version?
I saw in the upgrade from JB to KK thread (link: http://forum.xda-developers.com/show....php?t=2712039) has you use Odin to flash (with presumably stock KK) AP & BL images, so it seems that I would be well advised to make copies of my JB ones, should I wish to return? I wasn't sure if Titanium Backup worked at that level (the ROM/image level).
Perhaps I don't even need to do that as folks have already posted the needed files to return as detailed in this thread: http://forum.xda-developers.com/show....php?t=2559715 And perhaps there's no advantage to my M19 build versus the MJ5?
Finally, I wasn't sure if there were any good threads detailing the boot chain and where the currently public exploits take control (it seems that the KK bootloader has resisted exploitation, but something after that [kernel?] allows SS).