[Galaxy Tab 7.7 General] Androguide.fr:
HOW TO AVOID BRICKING YOUR TAB

The best advice I can give to people who haven't bricked their tab (already?^^) : DO NOT

EVER

WIPE ANYTHING WHILE RUNNING STOCK 7.7 ROMS

Here is what to do in order to flash a custom rom safely when coming from stock :

- Flash the latest cwm with ODIN

- Do NOT wipe anything

- Flash the custom rom of your choice

- Reboot recovery

- Wipe what you need to wipe

- Re-flash the custom rom

- flash the gapps or whatever

- Reboot, done.

Ok guys, I'm seeing more and more people bricking their 7.7 and, being one of the unlucky owners of a bricked p6810, I understand how stressful and annoying it can be.

I've been reviving my tab like a hundred times using this technique, as you'll most likely have to re-do that whole process everytime you wanna flash something.

There are two ways of reviving from superbrick I know of :

- The first is to flash a PIT file with ODIN that will repartition your tab for you.

I will not cover this method as hg42 already wrote a very detailed tutorial about this. This tutorial is about Galaxy Note but you can appIy it to our 7.7 and you'll find PITs for P6800 there. I will soon make pits for P6810 using the scripts provided in hg42's guide.

- The second way is to repartition your tab manually through adb. This is the method I'll try to teach you here.

Let's first be very clear :

- This won't get your tab back in its former state

- Your internal storage will shrink by a lot

- All your data will be lost

- No guarantee it works for you

- You'll most likely have to do that every time you flash

- Your tab might rebrick itself after some days, so you'll have to do this again, get used to it.

- If you can get Samsung to repair your tab then go ahead

- I'm not responsible for any further damage made to your tab

- You need a computer for this tutorial

Ok, you read the above carefully ? You are ok with it ? then let's begin !

Using the Android Debugging Bridge (adb) to revive your tab

Setting up your environment

Prior to anything, you need to download and install the android sdk, I won't cover the installation here, it's explained on developer.android.com and there are plenty of guides on how to get adb and the sdk on xda.

Make sure you install the platform-tools in the sdk manager.

Ok now I assume you got the sdk installed, so let's move on to the serious things.

1) How to open an adb shell ?

First, you're going to need the latest ClockWorkMod Recovery (a.k.a CWM), download and instructions on locerra's thread here

Then boot your tab in recovery (Maintain power+volume up buttons) and plug it into your computer via usb.

Then do the following :

a- On Windows

Navigate to the directory where you installed the sdk, and open the folder called "platform-tools" (e.g : go to C:\android-sdk\platform-tools if your sdk is installed in C:\android-sdk)

Press shift and do a right clic on an empty space in the folder, then select "open a command prompt here" (or something like that).

b- On Linux

Open a terminal window (ctrl+T)

Let's assume you put the sdk in a folder called "android-sdk", located at the root of your home folder (~/android-sdk).

Then you have to enter this in the terminal :

cd ~/android-sdk/platform-tools

So now, all the rest of the commands you'll have to enter are the same on windows and linux, as the adb shell will actually be running in your tablet.

2) Meet a new friend, he's called parted.

First, we are going to use parted to take a look at our partitions and their file systems, and eventually replace the corrupt partitions with clean, freshly created ones.

Then, you'll meet your other very good friend with a barbarian name : e2fsck (e2 stands for ext2, and fsck for file system check. Not that barbarian finally is it ?). He will check your filesystems and fix the possible errors they got.

Ok now we've made the presentations, let's go !

First make sure you read the following :

In the code boxes of this tutorial, there are symbols at each line start, DO NOT COPY IT with the rest of the command ! :

-the "$" represents your bash shell or command prompt

-the "#" represents the adb shell

-the"(parted)" represents the (parted) shell

-Each end of line means "press Enter".

-The partitions numbers are not the same on p6810 and p6800 (please report to this reference), so there will be two code boxes in the examples, one for p6810 and one for p6800, it's indicated in bold red but make sure you don't mix it up, that could screw your tab even more.

Ok here we go !

Issue the following in your terminal/command prompt :

$ adb shell
# parted /dev/block/mmcblk0
(parted) print

The output should look like this :

>>> P6810 <<<

Number Start End Size File system Name Flags
1 4194kB 25.2MB 21.0MB ext4 EFS
2 25.2MB 26.5MB 1311kB SBL1
3 27.3MB 28.6MB 1311kB SBL2
4 29.4MB 37.7MB 8389kB PARAM
5 37.7MB 46.1MB 8389kB KERNEL
6 46.1MB 54.5MB 8389kB RECOVERY
7 54.5MB 264MB 209MB ext4 CACHE
8 264MB 1137MB 872MB ext4 FACTORYFS
9 1137MB 15.3GB 4163MB ext2 DATAFS
10 15.3GB 15.7GB 470MB ext4 HIDDEN
11 15.7GB 15.8GB 8389kB FOTA

>>> P6800 <<<

The start/end values are wrong, please give me your p6800 output so I can update this.

Number Start End Size File system Name Flags
1 4194kB 25.2MB 21.0MB ext4 EFS
2 25.2MB 26.5MB 1311kB SBL1
3 27.3MB 28.6MB 1311kB SBL2
4 29.4MB 37.7MB 8389kB PARAM
5 37.7MB 46.1MB 8389kB KERNEL
6 46.1MB 54.5MB 8389kB RECOVERY
7 54.5MB 264MB 209MB ext4 CACHE
8 3054MB 3926MB 872MB ext4 MODEM/RADIO (not sure as I don't own this model)
9 264MB 1137MB 872MB ext4 FACTORYFS
10 1137MB 15.3GB 4163MB ext2 DATAFS
11 15.7GB 15.8GB 8389kB HIDDEN
12 15.8GB 15.9GB 8389kB FOTA

The superbrick MMC_CAP_ERASE bug that affects our tab apparently only corrupts the /system and /data partitions (sometimes, /cache can also get corrupt in the process, I cover this in the last part of this guide, "extra cases").

Your emmc chip on which resides those /data & /system partitions is corrupt at some places.

To give you an example, think of it as a chain of dashes :

-----------------------------------------------------

This dash chain is divided in two parts (our /system and /data partitions), I'll symbolize their length with "[]" for /system and "()" for /data :

[----------](-------------------------------------------)

So that's how it was on your tab before brick, but now it's bricked some blocks (the dashes "-" here) are corrupt. I'll symbolize them with "?" :

[--??--???-](--???-?-----------????-----------??-?--??--)

Now you figure the workaround don't you ? We need to move our /system & /data partitions to places that are clean, at the cost of reducing their sizes :

--??--???---???-?[-----------]????(-----------)??-?--??--

We will strive to give /system its original size, or something close to it, while we can sacrifice more of the /data partition.

Ok, enough theory, let's move on to practice.

Here, in parted, /system = FACTORYFS and /data = DATAFS

We are going to remove the /data partition first, so we have some space to work on.

Enter the following :

>>> P6810 <<<

(parted) rm 9

>>> P6800 <<<

(parted) rm 10

Now please refer to the output of (parted) print you had earlier, just scroll up a little in your terminal window. See those Start/End values ? Well check the end value of your DATAFS partition and remember it.

Here's an example for P6810 :

9 *START -->*1137MB 15.3GB*<-- END* 4163MB ext2 DATAFS

So now comes the boring part. We are going to try to make a new clean /data partition.

Seems easy but the problem is :

- if you try to make it too big, it'll get stuck and return an I/O error.

- if some blocks are corrupt between the start/end values you'll enter it will get stuck and return an I/O error.

In both cases you'll have to reboot recovery and re-enter this in your terminal :

# adb shell
# parted /dev/block/mmcblk0

So this is long and boring to find the right place and the right size. Don't be greedy on the size, as long as you get at least 150-200mb it's cool, you'll be able to expand that later.

First you're gonna try to put the original end value (15300 in the p6810 example up there) as the new end value. So for the same example, if you wanna try to make a 500mb /data partition, you're gonna use 14800 as start value and 15300 as end value.

Ok let's go (this is still an example for p6810, for the p6800 owners, use your own (parted) print results) :

(parted) mkpartfs primary ext2 14800 15300

It will output something like this :

writing per-group metadata : XX %

Here there are two options :

- You were lucky, it will complete up to 100% and return "(parted)", which case you just have to enter the following :

>>> P6810 <<<

name 9 DATAFS

>>> P6800 <<<

name 10 DATAFS

- You were not lucky, it got stuck before reaching 100%, which case you have to reboot your recovery, re-enter parted and try again with a smaller start/end gap, or reducing the end value, you got about 14gb of space to try to make your partition, so it's sure you can find somewhere to put your small partition, just requires some blind testing.

Just remember to try to put your /data partition quite close to the end (original end value), so you still have some space to find somewhere to put your /system partition.

So now we'll assume you managed to have mkpartfs complete till 100%

Type this to see your updated partition table :

(parted) print

Now we're going to repeat last step with the /system partition.

Issue this :

>>> P6810 <<<

rm 8

>>> P6800 <<<

rm 9

The /system partition is much more important than /data, so you want to try to have its size remaining the same (872mb).

At first, you can try to re-make the /system partition with the same start/end values. It's not likely to work but it's worth trying.

Here's an example on P6810:

(again, if you're on P6800, then use your own start/end values for the 9th partition (FACTORYFS), you get them by typing print in parted).

(parted) mkpartfs primary ext2 264 1137

Same thing here, if it doesn't complete, then reboot recovery, type :

$ adb shell
# parted/dev/block/mmcblk0

And repeat this step until you find somewhere it works : (where YYY - XXX = 872)

(parted) mkpartfs primary ext2 XXX YYY

Remember to limit your research between FACTORYFS original start value (264 for P6810) and the new DATAFS start value you made, so you keep the order of the partitions.

Once you found the right place (where "writing per-group metadata" completes till 100%), type this :

>>> P6810 <<<

name 8 FACTORYFS

>>> P6800 <<<

name 9 FACTORYFS

The hardest part is done, if you type this you should get a full table of partition, make sure no number is missing or disordered (1,2,3,4,etc...).

(parted) print

3) Meet another good friend : e2fsck

Now we've done our fresh and clean partitions, you must be thinking we're done, but we're not ^^

In fact the two partitions we made are using ext2 filesystem, but the /system partition's filesystem should be ext4 (like it was at the beginning).

There are two ways of converting an ext2 filesystem to ext4 that I know of :

- Simply formatting /system in cwm recovery will convert the filesystem to ext4. To do this, just head to "mounts & storages" and select "format /system".

If it gets stuck while formatting, reboot your recovery by pressing the power+volume-up buttons for about 15 seconds, and head to the next part, you have to do something before you can try to format it again.

- Or issuing this in terminal :

>>> P6810 <<<

# tune2fs –O dir_index,uninit_bg,has_journal /dev/block/mmcblk0p8

>>> P6800 <<<

# tune2fs –O dir_index,uninit_bg,has_journal /dev/block/mmcblk0p9

To make sure either of the two ways worked do this :

# parted /dev/block/mmcblk0
(parted) print

And look if FACTORYFS shows ext4.

If it does, reboot recovery, then on to next part. If it doesn't, then still reboot recovery and head to next part, after which I'll redirect you here to try again.

Now we are going to use e2fsck to check our new partitions for errors, but not only, it also fixes some erros and it will even for example create lost & found in /data

So let's go, we'll begin with /system. If you're still in the (parted) shell, use ctrl+c and type "adb shell", then issue the following :

>>> P6810 <<<

e2fsck -yfDC0 /dev/block/mmcblk0p8

>>> P6800 <<<

e2fsck -yfDC0 /dev/block/mmcblk0p9

This might take long, or not, this might get stuck, or not. Either way reboot recovery if it gets stuck or whatever, but do it again till it finishes properly.

This is what my /system e2fsck final output looks like (p6810) :

/dev/block/mmcblk0p8: ***** FILE SYSTEM WAS MODIFIED *****
/dev/block/mmcblk0p8: 2636/53312 files (1.2% non-contiguous), 101948/212890 blocks

If you got 0.0% or like less than 5% in "(X.X% non-contiguous)" this is a good sign.

Now reboot recovery and let's do the same for /data :

>>> P6810 <<<

# e2fsck -yfDC0 /dev/block/mmcblk0p9

>>> P6800 <<<

# e2fsck -yfDC0 /dev/block/mmcblk0p10

Same thing here, if it gets stuck then reboot recovery and do it again.

Here you should get 0.0% non contiguous. If you don't, in cwm do wipe data/factory reset, then reboot recovery and do this e2fsck again.

Ok now you got both clean e2fsck, (if you still have an ext2 FACTORYFS then now is the time to go back to try converting ext2 to ext4 again)

Make sure the e2fsck still are clean by doing this (it should be quick this time) :

>>> P6810 <<<

# e2fsck -cy /dev/block/mmcblk0p8
# e2fsck -cy /dev/block/mmcblk0p9

>>> P6800 <<<

# e2fsck -cy /dev/block/mmcblk0p9
# e2fsck -cy /dev/block/mmcblk0p10

Now you should be nearly good to go ! :laugh:

Download the cm9/cm10-based rom you want, make sure you check known issues and that you like this rom because everytime you'll want to flash a rom it's likely you'll have to do the whole e2fsck part again, or even sometimes the whole guide.

Now reboot in recovery and flash the rom. Two options :

- it flashes, then reboot, pray and be patient, if it takes more than 15 minutes to boot first time, then reboot it again, do this a few times if it doesn't boot, it might eventually do. If it doesn't, then reboot recovery and redo the e2fsck command for both /data and /system, let it fix things if it has to, then reboot again. Anyway it should have booted by now.

- flashing gets stuck : make sure you waited at least 5 minutes then reboot recovery---> wipe data/factory reset---> wipe dalvik cache---> reboot recovery---> adb shell and redo the e2fsck on both /data and /system, then try flashing again.

DO NOT FLASH THE GAPPS NOW, that will screw all you just done ! If you need the gapps then head to the following section of this guide.

4) Installing the gapps

If you flash the gapps after flashing the rom you'll be screwed, you'll have to redo the e2fsck part and maybe even the parted, and I know you don't want to.

So the workaround is to add the gapps to the cm-based rom you downloaded.

It's easy, just follow me :

Open the zipped rom you downloaded with 7zip or WinRar (Windows), or with Archive Manager or else (Ubuntu). Do not extract it, we'll modify the zip directly.

Do the same with the gapps, so you have both archive side to side.

In the rom, you have boot.img, and two folders : "META-INF" and "system". We will modify things in "system" folder ONLY. Open "system" folder.

In the gapps we will only use things from the "system" and "optional" folders.

The rest is pretty easy to figure out. In the gapps's "system" and "optional" folders you have folders which have the same name as some folders in "system" of the rom.

Just copy/replace everything that is in those folders of the gapps to the corresponding folders of the rom. Don't forget to do that with both "system" AND "optional" folders of the gapps.

When it's done just close the freshly modified rom, copy it to your tab's external sdcard and flash it.

If you don't have an external sdcard, then reboot recovery, copy the rom to the "platform-tools" folder of your android-sdk and rename it rom.zip.

Then return to your terminal and do the following :

$ adb push rom.zip /sdcard

It will now be in your internal sdcard (remember you shrinked it earlier so make sure the rom doesn't take all the space).

5) Expanding your internal storage

I don't recommend you do this the first time you follow this guide.

It might screw your /data partition so you have to do the whole process I describe in this guide again.

Anyway if you wanna try, this allowed me to earn a few extra gigs (never managed to get back more than 4gb and boot).

Here's what to do :

>>> P6810 <<<

$ adb shell
# parted /dev/block/mmcblk0
(parted) resize 9

>>> P6800 <<<

$ adb shell
# parted /dev/block/mmcblk0
(parted) resize 10

This will output something like :

Start ?
End ?
writing per-group metadata : XX %

You can only move the end value in fact, trying to change the start value will return an error. Try doing this to earn like 250mb at a time so it doesn't get stuck. Good luck.

6) Extra cases

If when booting in recovery, the recovery says something like "can't read /cache/recovery/last-log, Read-Only file system" then your /cache partition is corrupt.

Then you'll need to recreate it with parted. /cache is quite small (209mb) so it should be easy to have "writing per-group metadata" finishing.

Here are the commands to remove and recreate /cache with parted (it's the same on both models) :

$ adb shell
# parted /dev/block/mmcblk0
(parted) print
(parted) rm 7
(parted) mkpartfs primary ext2 XX YY (where YY - XX = 209 and YY < FACTORYFS start value)