I was given a Galaxy Tab S by a relative who works in a cell phone store. It was a demo device, and it had demo mode enabled. I initially attempted to reboot into recovery and do a wipe from there, but an error came up informing me that "MDM" had blocked this option (I assume MDM to mean manufacturer demo mode). The tablet was still working at this point, so I rebooted and got the exact model number, SM-T700. I googled for a bit and found the recommendation to be to reinstall the firmware. I've done a lot of ODIN flashes before, so I downloaded the correct firmware from the official firmware post here on XDA, rebooted to download mode, and flashed it without issues.
After 30 minutes, the tablet still just showed the Samsung boot screen. I did a hard reboot with volume up + power, and left it. After another 30 minutes, it still didn't show anything. I rebooted to download mode and tried flashing again. Same result. I rebooted to recovery and tried to wipe the device from there. MDM block.
After more searching, I decided to use the PIT file and the firmware file in ODIN. I've had to use PIT files a couple times before, so I was very careful in checking to ensure I had the correct one. I am very confident I did. I flashed that, and still the tablet would not boot.
I then decided to install TWRP and see if I could wipe from there. TWRP gave me some useful information: it returned that it could not mount any of the partitions on the device. 'could not mount /system', 'could not mount /data', etc.
I've done a lot of googling and reading since then, but I can't seem to find anybody else with the result. The closest thing I can find is a similar situation on some ASUS tablets, but the solution would definitely not work here. The only other thing I can find is people recommending to flash the PIT file, which I have no tried a second time and still does not work.
Does anybody have any suggestions? I don't know what else to do.