Recently I purchased a used Galaxy Tab S 10.5 LTE [SM-T807a], and set it up for use as a WiFi tablet. I have a phone with a hotspot, so that part isn't really necessary. I had rooted it with KingRoot, and was attempting to shift it over to ChainFire's SuperSU program. As this had not been successful, I restored KingRoot, and as I had root reestablished, I tried using FlashFire to flash TWRP for the TabS 10.5 LTE [chagalllte]. This reported success, and the system rebooted; upon reboot, I got the following error:
System Software Not Authorized by AT&T has been found on your tablet. Please turn off your tablet and go to the nearest AT&T store for help.
I have made multiple attempts to recover through Odin 3; it has failed on every attempt. Hoping someone can help; if naught else, might have the correct ROM for this tablet. TIA.