Originally Posted by Marco Lomas
I recomend a lot install the jb firmware and not usibg the ota service, for avoid phone bricks, also, if you install the jb firmware with rsd lite, you have the posibility to return to ics without brick
(i dont know why you will return but its a extra)
Enviado desde mi XT890 mediante Tapatalk
That's not entirely true that u cant go back when u have installed it by OTA update. With rsd and with ota update u will upgrade some files exactly the same way with both methods, that must not be downgraded. Those files are the bootloader and partition files aka motoboot, gpt, dns, ifwi and (bos?).
I recommend if u ever want to downgrade, flash all things manually. Flash the boot, recovery and system partitions only when going from JB to ICS and erase the cache/data partition or u will get a software-brick. Is fixable though.
But to go from ICS to JB (upgrade), I go with Marco for the rsd flash. Especially when rooted i think. There is a small change that u will relock the bootloader, but i don't know that for sure. However it should work with OTA in theory if u have stock recovery...