[Tutorial] - Fixing a bricked system

[TheStranger]

Sorry, but dump /dev/sdcarda7 not worked!
What is the right syntax - searched by google but not find.

Code:

/ # dump /dev/sdcarda7
[ 1123.140000] SQUASHFS error: zlib_inflate error, data probably corrupt
[ 1123.150000] SQUASHFS error: squashfs_read_data failed to read block 0x1a2cf9d
[ 1123.160000] SQUASHFS error: Unable to read fragment cache entry [1a2cf9d]
[ 1123.160000] SQUASHFS error: Unable to read page, block 1a2cf9d, size be14
[ 1123.170000] SQUASHFS error: Unable to read fragment cache entry [1a2cf9d]
[ 1123.180000] SQUASHFS error: Unable to read page, block 1a2cf9d, size be14
[ 1123.180000] SQUASHFS error: Unable to read fragment cache entry [1a2cf9d]
[ 1123.190000] SQUASHFS error: Unable to read page, block 1a2cf9d, size be14
-/bin/sh: dump: Input/output error
/ #

[Deak Phreak]

It is the same command the install script uses to backup the firmware

dd if=/dev/sdcarda7 of=/vp_mnt/sd/sdcarda7_backup.bin

Adjust the output to match the path to your SD card. When I said chat, I was talking about IRC. There is a link to load it on the forums.

[TheStranger]

OK, dump worked. I extract the bin in my virtual ubuntu system.
Where can i see witch firmware it is?

[Deak Phreak]

I am not sure how to find the actual version from the firmware. You could try mounting it from the SD card and then running the "boot up" script to see if you can get the device to load before actually flashing it. I don't know all the commands off-hand though. You can also try flashing your dump to sdcard6 and see what happens.

is0-mick could most likely help out further in the IRC though.

[is0-mick]

From what you posted it seems that sdcarda6 is where your system is trying to boot from.
/dev/sdcarda6 on /system type squashfs (ro,relatime)

What you need is a good copy, or pre-patched copy of the SAME version of firmware as what was originally on your tablet.
It's no good backing up sdcarda7 as it will be a different version, as every time the system is updated it swaps between A6 and A7.

So...
1) get a good copy of firmware (same version (original or patched) as what was on your tab originally)
2) dd if=/vp_mnt/sd/goodfirmware.bin of=/dev/sdcarda6
3) app_destroyer.x -f
4) reboot.

That should do it.
Mick

[TheStranger]

Hi is0-Mick,
thanks for reply. I have a backup from device befor i patched first time. Can i compare the firmware versions or another question, in which file is the version stored?

[Deak Phreak]

you can check the signature file from sdcard7 with your original backup. If they match, it may be safe to assume they are the same or close enough.

[TheStranger]

Yes it be the same - i will try now.

[TheStranger]

No not worked - get same errors.
I compare the both signature-files and they have the following data:

Code:

2015-03-12 17:20:11
dev
vicsiu

But in the bootup they get a warning with another datetime:

Code:

2015-12-17 16:26:59
dev
vicsiu

I think they dont flash it.

I do this with my originally firmware-backup:

Code:

1. format the SD as FAT32
2. copy my backup.bin to SD
3. starts putty and connect
4. check if SD is mount (ls /media/scardb1)
5. Flash
if=/media/sdcardb1/sdcarda6_backup.bin of=/dev/sdcarda6
53816+0 records in
53816+0 records out
27553792 bytes (26.3MB) copied, 18.888677 seconds, 1.4MB/s
6. kill fastboot
app_destroyer.x -f
[ 5396.110000] SQUASHFS error: zlib_inflate error, data probably corrupt
[ 5396.120000] SQUASHFS error: squashfs_read_data failed to read block 0x1a06461
[ 5396.130000] SQUASHFS error: Unable to read fragment cache entry [1a06461]
[ 5396.130000] SQUASHFS error: Unable to read page, block 1a06461, size c512
[ 5396.140000] SQUASHFS error: Unable to read fragment cache entry [1a06461]
[ 5396.150000] SQUASHFS error: Unable to read page, block 1a06461, size c512
[ 5396.150000] SQUASHFS error: Unable to read fragment cache entry [1a06461]
[ 5396.160000] SQUASHFS error: Unable to read page, block 1a06461, size c512
-/bin/sh: app_destroyer.x: Input/output error

Can i clear or format the old sdcarda6?

Another Question is - i'll do it all in windows putty - must i'll do it in linux too?

[Deak Phreak]

try to unmount sdcard6 and then flash your original backup again. I think it is umount /dev/sdcarda6 or something like that. Maybe it is not flashing because it is in use. It does say "27553792 bytes (26.3MB) copied, 18.888677 seconds, 1.4MB/s" which seems like it worked though.