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I unlocked the bootloader of my Xperia P (LT22i) before I could take a backup of the TA partition (which stores DRM keys, IMEI code, etc.)

Now I've read on several XDA threads and other websites that TA can not be backed up after the bootloader has been unlocked. And that once it's unlocked, everything in there is gone.

However, when I used the latest version of Backup TA on my phone, it could detect the presence of and backup the TA partition.

Now I'm not sure if the backup it created is a valid TA backup so is there a way to check its integrity and/or parse the contents of TA.img to see if it does contain valid DRM keys and other stuff?

P.S. I tried opening TA.img in a hex editor and searching for my phone's IMEI number. I found it in the file. I also found references to "marlin" and quite a few X.509 certificates. The uncompressed size of my phone's TA.img is 512 KB (5,24,288 bytes)

And if it helps, here's the part of the log from Backup TA where it finds and backs up the TA partition:

--- mmcblk0boot0 ---
Searching for Operator Identifier...-
Searching for Operator Name...-
Searching for Rooting Status...-
Searching for S1 Boot...-
Searching for S1 Loader...-
Searching for S1 Hardware Configuration...-

Partition found!

=======================================
 BACKUP TA PARTITION
=======================================
1024+0 records in
1024+0 records out
524288 bytes (512.0KB) copied, 0.030456 seconds, 16.4MB/s

=======================================
 INTEGRITY CHECK
=======================================
OK

=======================================
 PULL BACKUP FROM SDCARD
=======================================
2437 KB/s (524288 bytes in 0.210s)

=======================================
 INTEGRITY CHECK
=======================================
OK

=======================================
 PACKAGE BACKUP
=======================================

7-Zip (A) 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18
Scanning

Creating archive ..\backup\TA-backup-20140722.010348.zip

Compressing  TA.blk
Compressing  TA.img
Compressing  TA.md5
Compressing  TA.serial
Compressing  TA.timestamp
Compressing  TA.version

Everything is Ok

*** Backup successful. ***
  • Why is it important to you to make a backup of this partition? – unforgettableid Oct 9 '15 at 1:27
  • @unforgettableid Because it's my understanding that this partition stores the DRM keys for several Sony proprietary software including Mobile Bravia Engine and without a backup of this partition, Bravia Engine functionality would cease to function. – Vinayak Oct 9 '15 at 5:41
1

It should be possible to check via the service menu of the phone. Go to calls, enter *#*#7378423#*#* and go to service info-configuration (somewhere at the bottom). The lines should end with [Key OK][Active].

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