My C1905 came out of the box with branded 15.1.C.2.8 firmware. One of the first things I did after rooting the device was backing up my TA partition, knowing that I will sooner or later unlock the bootloader. However, I then cross-flashed unbranded C2005 15.2.A.2.5 firmware. My questions are:
1)Do I need to backup TA partition again on a new firmware to be able to relock my bootloader without changing it? Does the TA partition vary between firmwares?
2)Will changing my firmware again to official 4.2.2 for C1905 (which should be released within 2 months) require my to back it up again? Is the C2005's TA partition different than C1905's?
3)Just out of curiousity, what exactly does the TA partition contain? From what I've read, it stores unique "DRM keys", but that doesn't tell me much. Are these keys linked with any hardware (like - for comparison - Samsung's "EFS" folder stores IMEI, MAC adress product code etc and without it, phone has very limited capabilities), or is it just more like "locked bootloader certificate"?
I just want to clear that up, thanks in advance for answering.