TF700T complete flash layout

[utx]

I spent some time in analyzing of flash layout. The comprehensive description below attempts to map each byte of the flash and describes way to extract it.

I would be glad if somebody could provide more detailed info about bootloader, signatures, DRM etc.

Patches are welcome.

mmcblk0 layout
All dumps were done on Asus Eee Pad Transformer Infinity TF700T, 64GB version, firmware 9.4.5.26, locked

mmcblk0 off-partition section
Offset: 0 (0x0)
Size: 38273024 (0x2480000)
Read command: busybox dd if=/dev/block/mmcblk0 of=/mnt/sdcard/mmcblk0pre1.img bs=524288 count=73

Offset: 0 (0x0)
Size: 3670016 (0x380000)
Contains: Zeroes
Purpose: Unknown
Extract command: dd if=mmcblk0pre1.img of=mmcblk0pre1s1.img bs=3670016 count=1
Process command: tr -d '\0' <mmcblk0pre1s1.img >mmcblk0pre1s1nz.img # mmcblk0pre1s1nz.img must be empty file

Offset: 3670016 (0x380000)
Contains: Recovery kernel image followed by zeroes
Size: 8388608 (0x800000)
Extract command: dd if=mmcblk0pre1.img of=mmcblk0pre1s2.img bs=524288 skip=7 count=16
Process commands:
perl split_bootimg.pl mmcblk0pre1s2.img 
mkdir mmcblk0pre1s2.img-ramdisk
cd mmcblk0pre1s2.img-ramdisk
zcat ../mmcblk0pre1s2.img-ramdisk.gz | cpio -i
cd ..
# end Process commands

Offset: 12058624 (0xb80000)
Contains: Regular boot kernel image followed by zeroes
Size: 8388608 (0x800000)
Extract command: dd if=mmcblk0pre1.img of=mmcblk0pre1s3.img bs=524288 skip=23 count=16
Process commands:
perl split_bootimg.pl mmcblk0pre1s3.img 
mkdir mmcblk0pre1s3.img-ramdisk
cd mmcblk0pre1s3.img-ramdisk
zcat ../mmcblk0pre1s3.img-ramdisk.gz | cpio -i
cd ..
# end Process commands

Offset: 20447232 (0x1380000)
Contains: Block of 16 bytes followed by 0x2de0 hexadecimal numbers followed by FF
Size: 12288 (0x3000)
Extract command: dd if=mmcblk0pre1.img of=mmcblk0pre1s4.img bs=524288 skip=39
Vital data:
Extract command: dd if=mmcblk0pre1s4.img of=mmcblk0pre1s4ss2.img bs=4096 skip=3
Binary part of vital data:
Extract command: dd if=mmcblk0pre1s4ss1.img of=mmcblk0pre1s4ss1ch1.img bs=16 count=1
Hexadecimal part of vital data:
Extract command: dd if=mmcblk0pre1s4ss1.img of=mmcblk0pre1s4ss1ch2.img bs=16 count=734 skip=1
Process command: unhex <mmcblk0pre1s4ss1ch2.img >mmcblk0pre1s4ss1ch2bin.img
FF part of vital data:
Extract command: dd if=mmcblk0pre1s4ss1.img of=mmcblk0pre1s4ss1ch3.img bs=16 skip=735
Process command: tr -d '\377' <mmcblk0pre1s4ss1ch3.img >mmcblk0pre1s4ss1ch3nff.img # mmcblk0pre1s4ss1ch3nff.img must be empty file
Zeroes:
Extract command: dd if=mmcblk0pre1s4.img of=mmcblk0pre1s4ss1.img bs=4096 count=3
Process command: tr -d '\0' <mmcblk0pre1s4ss2.img >mmcblk0pre1s4ss2nz.img # mmcblk0pre1s4ss2nz.img must be empty file
Purpose: Probably encrypted bootloader

mmcblk0p1
Offset: 38273024 (0x2480000)
Size: 805306368 (0x30000000)
File system size: 196608 * 4096 = 805306368 (fully occupies partition)
Format: Linux ext4 filesystem
Mounted at: /system
Mount options: read only, extended attributes, ACL
Permissions: only root can manipulate
Contains: Base system and embedded applications
Purpose: Base system

mmcblk0p2
Offset: 843579392 (0x32480000)
Size: 448790528 (0x1ac00000)
File system size: 109568 * 4096 = 448790528 (fully occupies partition)
Format: Linux ext4 filesystem
Mounted at: /cache
Mount options: read/write, no SUID, no device nodes, no atime
Permissions: only root can manipulate, UID system and GID cache can read and write
Contains: Cache
Purpose: Application cache
Note: The volume has the same UUID as mmcblk0p1

mmcblk0p3
Offset: 1292369920 (0x4d080000)
Size: 2097152 (0x200000)
File system size: 512 * 4096 = 2097152 (fully occupies partition)
Linux rev 1.0 ext3 filesystem
Not mounted
Permissions: GID system can manipulate
Contains: Empty file system
Purpose: Recovery /misc
Referenced by: /system/lib/libandroid_runtime.so recovery ramdisk: /etc/recovery.fstab
Note: File system is referenced in recovery as emmc, not ext3!

mmcblk0p4
Offset: 1294467072 (0x4d280000)
Size: 855638016 (0x33000000)
File system size: 208896 * 4096 = 855638016
Linux rev 1.0 ext3 filesystem
Not mounted
Permissions: GID system can manipulate
Contains: Empty file system
Purpose: Recovery /staging
Referenced by: recovery ramdisk: init.rc /etc/recovery.fstab

mmcblk0p5
Offset: 2150105088 (0x80280000)
Size: 5242880 (0x500000)
File system size: 5092 * 1024 = 5147488
Format: FAT32 file system, no partition table, MS-DOS "Non-system disk" boot block
Not mounted
Permissions: only root can manipulate
Contains: File system with files:
Serial numbers (ISN, PPID, SSN, UUID)
Calibration data (AL3010 light sensor, AMI304 magnetic sensor, KXTF9 motion sensor)
Purpose: Device specific unique system data, mounted as /btmac during Android boot
Referenced by: /system/bin/wifimacwriter /system/bin/brcm_patchram_plus /system/bin/sensors-config /system/bin/sixpair ramdisk: /init recovery ramdisk: /etc/recovery.fstab /init

mmcblk0p5 off file-system area
Offset in section: 5147488 (0x4e8b60)
Size: 28672 (0x7000)
Read command: busybox dd if=/dev/block/mmcblk0p5 of=/mnt/sdcard/mmcblk0p5s2.img bs=1024 skip=5092
Process command: tr -d '\0' <mmcblk0p5s2.img >mmcblk0p5s2nz.img # mmcblk0p5s2nz.img must be empty file

mmcblk0p6
Offset: 2155347968 (0x80780000)
Size: 524288 (0x80000)
Format: binary data
Permissions: UID drm can manipulate
Contains: 208 bytes of binary data, the rest are zeroes
Purpose: DRM, probably contains encrypted DRM key
Referenced by: /system/bin/wvdrmserver /system/vendor/lib/drm/libdrmwvmplugin.so

mmcblk0p7
Offset: 2155872256 (0x80800000)
Size: 5242880 (0x500000)
Format: empty
Contains: Zeroes
Purpose: Unknown

mmcblk0p8
Offset: 2161115136 (0x80d00000)
Size: 61415620608 (0xe4ca80000)
File system size: 14994040 * 4096 = 61415587840
Format: Linux ext4 filesystem
Mounted at: /data
Mount options: read/write, no SUID, no device nodes, no atime
Permissions: only root can manipulate, read and write are directory specific
Contains: User applications, user data, and virtual internal SD card
Note: /data/media is mounted via UID/GID stripping FUSE as /mnt/sdcard

mmcblk0p8 off file-system area
Offset in section: 61415587840 (0xe4ca78000)
Size: 32768 (0x8000)
Read command: busybox dd if=/dev/block/mmcblk0p8 of=/mnt/sdcard/mmcblk0p8s2.img bs=4096 skip=14994040

mmcblk0 off-partition section
Offset: 63576735744 (0xecd780000)
Size: 524288 (0x80000)
Read command: busybox dd if=/dev/block/mmcblk0 of=/mnt/sdcard/mmcblk0post8.img bs=524288 skip=121263
Process command: tr -d '\0' <mmcblk0p8s2.img >mmcblk0p8s2nz.img # mmcblk0p8s2nz.img must be empty file

Offset: 63576735744 (0xecd780000)
Offset in section: 0 (0x0)
Size: 507392 (0x7be00)
Contains: Zeroes
Purpose: Unknown
Extract command: dd if=mmcblk0post8.img of=mmcblk0post8s1.img bs=507392 count=1
Process command: tr -d '\0' <mmcblk0post8s1.img >mmcblk0post8s1nz.img # mmcblk0post8s1nz.img must be empty file

Offset: 63577243136 (0xecd7fbe00)
Offset in section: 507392 (0x7be00)
Size: 16896 (0x4200)
Contains: EFI Partition table (partition names: APP, CAC, MSC, USP, PER, YTU, CRA, UDA)
Extract command: dd if=mmcblk0post8.img of=mmcblk0post8s2.img bs=512 skip=991
Purpose: Partition table


Total size of mmcblk0: 63577260032 (0xecd800000)


Notes:
can manipulate = can read, write partition vital data, only root can mount
can read, write = can read, write partition file system contents
Read commands are ran on the Transformer
Extract and process commands are run anywhere, with pre-read image file in the current directory.
You need dd with large files support. Vanilla dd on TF700T does not support large files. Busybox dd does.

Dropbox link to Asus_Transformer_Infinity_TF700T/flash_layout.txt

 

[_that]

Wow, thanks for this detailed analysis - much more detailed than mine.

So what can I add to your research?

Tegra-based systems have another partition table, which has a proprietary layout and an unknown purpose (maybe just important for NVFlash and for flashing blobs?). Looking at the flash.cfg in the NVFlash package from AndroidRoot.mobi, we can get the Tegra partition layout and partition names:

Partition number 1 is missing in the list, maybe it contains the extremely well-hidden APX mode recovery code or even the answer to life, the universe and everything.

The following 3 partitions are located at the beginning of mmcblk0 and their contents are apparently encrypted with a device-specific key. For some reason, with ICS-based ROMs it reads as all zeros; in JB-based ROMs additional mmcblk0boot0 and mmcblk0boot1 partitions appear which together cover this area. The "bricksafe.img" in the nvflash guide covers these 3 partitions.

2 BCT: Tegra Boot Configuration Table - 3145728 bytes
3 PT: Tegra Partition Table - 524288 bytes
4 EBT: Bootloader - 8388608 bytes

You already know the following 2:

5 SOS: Recovery kernel - 8388608 bytes
6 LNX: Linux kernel - 8388608 bytes

Then some more funny ones:

7 CER: I think this stands for "Certificate" and contains the bootloader unlock token. - 8388608 bytes. If I calculated correctly, this is at 0x1380000 into mmcblk0. Saved as "unlock-token.img" in the nvflash guide.
8 IMG: no idea what this is for - 8388608 bytes
9 GP1: space for a GPT partition table, maybe unused - 1048576 bytes

Now the regular partitions follow (p1 to p8):

10 APP: p1 = /system (Android OS)
11 CAC: p2 = /cache (for communication between Android and recovery)
12 MSC: p3 ="misc", whatever that is. On the TF101 it was used for bootloader commands.
13 USP: p4 = The update staging partition. Update blobs are copied here and flashed to the correct partition by the bootloader.
14 PER: p5 = device-specific config in a FAT filesystem
15 YTU: p6 = Apparently the DRM key. Confirmed to be overwritten with 0 by the unlocking process.
16 CRA: p7 = unknown (reserved for crash dumps?)
17 UDA: p8 = /data (Android user data)

And finally:

18 GPT: the EFI partition table that is actually used by the kernel

 

[utx]

Well, it seems, that something (ICS stock kernel, hardware) hides contents of the first (at most) 0x380000 bytes of flash.

I am locked, and I have some token at 0x1380000 as well.

I am still thinking about a way to unlock, keep access to nvflash, and upgrade to JB keeping DRM working, even at cost of using stock system. That is why I wanted to backup and analyze everything and find all keys and signatures.

It would be also nice to know, whether there are areas of flash with hardware or kernel write lock.

 

[_that]

Well, it seems, that something (ICS stock kernel, hardware) hides contents of the first (at most) 0x380000 bytes of flash.

I am locked, and I have some token at 0x1380000 as well.

Yes, before unlocking I had something very similar to you there - a 16 byte header followed by some hexdump. I don't know what it was. It was overwritten by the unlock process with a 4 byte data block prefixed with a "-SIGNED-BY-SIGNBLOB-" header and followed by 256 bytes of what looks like a digital signature, very similar to the signed update blobs.

I am still thinking about a way to unlock, keep access to nvflash, and upgrade to JB keeping DRM working, even at cost of using stock system. That is why I wanted to backup and analyze everything and find all keys and signatures.

Definitely back up the YTU partition before unlocking (p6) and then make the nvflash backups - but maybe the key must match something that is broken by the unlocking process, or it is renewed periodically, etc., so it might not help. Maybe try using DRM before unlocking and watch if the content of the partition changes over time.

It would be also nice to know, whether there are areas of flash with hardware or kernel write lock.

Never tried to write directly to the block device - too scared to break something.

---------- Post added at 09:32 PM ---------- Previous post was at 09:28 PM ----------

Another small addition:

Note: /data/media is mounted via UID/GID stripping FUSE as /mnt/sdcard

This FUSE trick also makes /mnt/sdcard case-insensitive.

 

[ostar2]

I just thought of something. What if you launched a data recovery process and recovered the DRM keys for the device?

 

[_that]

I just thought of something. What if you launched a data recovery process and recovered the DRM keys for the device?

How do you define "data recovery process"? You cannot recover data that has been overwritten.

 

[utx]

How do you define "data recovery process"? You cannot recover data that has been overwritten.

Well, if the DRM partition is write enabled, it may be possible to restore its contents, if you backed it up before unlock (it is probably per-device unique). But it could be insufficient. Locked bootloader can be different than unlocked bootloader, and may drop cipher needed for DRM decihering. It is just a theory. Somebody could proof it or falsify, if:

1) Backed all accessible data before unlock.

2) Unlocked (and to be safe, also made brickproof image).

3) Recovered the data creates in step 1.

Will DRM work then? Or did we need the contents of (currently inaccessible) locked stock data of the first megabytes?

But I see no way, how to back-up first megabytes of locked device (on ICS; JB is not as interesting for us, once you upgrade to JB, you cannot create brickproof image for nvflash).

I even don't know, which part of the subsystem causes these megabytes being reported as zeroes. Is it stock Asus ICS kernel? Is it bootloader? Is it a hardware lock on the flash device?

 

[ostar2]

Good idea, but what I meant by "Data Recovey". Is restoring the deleted data from that filesystem/partition.

 

[_that]

Good idea, but what I meant by "Data Recovey". Is restoring the deleted data from that filesystem/partition.

I see, so I assume you assume you had a backup before.

Somebody (maybe you?) could try roughly the following sequence:

- get new TF700
- update to 9.4.5.26. if it's already newer, forget nvflash, but the rest could still work.
- root it using debugfs
- make a backup of /dev/block/mmcblk0p6
- do some DRM-dependent stuff and check that it works
- after some days, make another backup of /dev/block/mmcblk0p6 and compare if anything has changed. If the key is static, maybe restoring after unlocking could work. If not, chances are high that it doesn't work.
- unlock (this erases mmcblk06 and voids warranty)
- optional, but very useful: install AndroidRoot hacked bootloader to make blobs for nvflash, then use nvflash to backup all partitions
- restore backup of /dev/block/mmcblk0p6
- try if DRM still works

 

[firetech]

I see, so I assume you assume you had a backup before.

Somebody (maybe you?) could try roughly the following sequence:

- get new TF700
- update to 9.4.5.26. if it's already newer, forget nvflash, but the rest could still work.
- root it using debugfs
- make a backup of /dev/block/mmcblk0p6
- optional, but very useful: install AndroidRoot hacked bootloader to make blobs for nvflash, then use nvflash to backup all partitions
- do some DRM-dependent stuff and check that it works
- after some days, make another backup of /dev/block/mmcblk0p6 and compare if anything has changed. If the key is static, maybe restoring after unlocking could work. If not, chances are high that it doesn't work.
- unlock (this erases mmcblk06 and voids warranty)
- restore backup of /dev/block/mmcblk0p6
- try if DRM still works

To install AndroidRoot bootloader and by that getting nvflash blobs, you have to unlock first... The order of your steps is therefore wrong.

 

[_that]

To install AndroidRoot bootloader and by that getting nvflash blobs, you have to unlock first... The order of your steps is therefore wrong.

Oops, thanks for noticing. I edited my post.

 

[AbdouRetro]

what if we were to read from the NAND externally (RAW)....xbox 360 style...wouldn't that be the same as nvflash....

except that the three partitions in question are encrypted with a key that is probably unique per Tegra...
2 BCT: Tegra Boot Configuration Table - 3145728 bytes
3 PT: Tegra Partition Table - 524288 bytes
4 EBT: Bootloader - 8388608 bytes

but I would suppose it wouldn't be a problem since a raw flash would restore everything back to normal...even if we can't read it..the CPU can..and that's all that matters.

---------- Post added at 11:21 AM ---------- Previous post was at 11:13 AM ----------

never mind...its a BGA

 

[W3ber]

I see, so I assume you assume you had a backup before.

Somebody (maybe you?) could try roughly the following sequence:

- get new TF700
- update to 9.4.5.26. if it's already newer, forget nvflash, but the rest could still work.
- root it using debugfs
- make a backup of /dev/block/mmcblk0p6
- do some DRM-dependent stuff and check that it works
- after some days, make another backup of /dev/block/mmcblk0p6 and compare if anything has changed. If the key is static, maybe restoring after unlocking could work. If not, chances are high that it doesn't work.
- unlock (this erases mmcblk06 and voids warranty)
- optional, but very useful: install AndroidRoot hacked bootloader to make blobs for nvflash, then use nvflash to backup all partitions
- restore backup of /dev/block/mmcblk0p6
- try if DRM still works

Correct order maybe.
- get new TF700
- update to 9.4.5.26.
- root it using debugfs
- make a backup of /dev/block/*.*
- unlock (this erases mmcblk06 and voids warranty)
- install AndroidRoot hacked bootloader to make blobs for nvflash
- restore backup of /dev/block/mmcblk0p6
- try if DRM still works

Q1:If i backed up 9.4.5.26 all block image.After i updated 9.4.5.30 can i get the nvflash blob from backed up images?No way to dig out the blob key from the backup?

 

[_that]

Q1:If i backed up 9.4.5.26 all block image.After i updated 9.4.5.30 can i get the nvflash blob from backed up images?No way to dig out the blob key from the backup?

No way - the BCT, bootloader, etc. is not visible to the kernel at all (so it's not included in your images), and I don't know which kind of magic the blob creation tool uses, but I assume it's more than reading stuff from the nand.