Default [Q] AT&T E970 Internal Storage Read-only

After updating my AT&T E970 to 4.1.2 via OTA, the internal storage of my phone became read-only. Also the camera stopped working. From my research, it seems the only way to fix this is via rooting the device. However, I've tried frameroot and but did not have any lock. With ZV9, I know the issue is the /sdcard folder is not accessible. I also tried to run mount from Terminal Emulator, it seems the internal storage is not mounted at all.

Finally, after running out of ideas, I put my phone into download mode and flash teenybin in LGNPST. I got into a reboot loop so I had to flashed it back to stock 20j.

Found this post on how to fix the camera issue:
But I was not able to flashing 11c rom (bootup is stuck at AT&T screen). Had to revert back to stock 20j.
I also tried using adb to reboot into bootloader and fastboot mode, but the phone just reboot itself without going into bootloader mode.

I would really appreciate if someone can shed some light on how to solve this. Much obliged.

Baseboard version - APQ8064/MDM9x15M
Kernal version 3.4.0
Build Number JZO54K
Software Version E97020j