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[Q] ?? How to backup Firmware on stock device

51 posts
Thanks Meter: 12
By mobilemedic, Member on 18th January 2014, 05:44 AM
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I have a Samsung Relay that is rebranded by Cellular One of North East AZ. They have a fancy super thin sticker over the Tmobile logo on the glass. lol... But the firmware in the device is branded by Cellular One.

I cannot find that firmware anywhere and want to know if anyone has any directions on how to back up the firmware so It could be loaded onto a t-mobile Relay to "brand" it for Cellular One.

Appreciate any help you can offer.


(I normally play in CDMA world, but I moved to po dunk nothing ville and VZW Sucks here, so had to go with Cell One. First real experience with GSM)
19th January 2014, 02:51 PM |#2  
Hadley, MA
Thanks Meter: 145
I've never done this before and I'm not 100% sure if it can be done. But there probably are ways if you're clever enough. So here's what I would try if I were in your position:

1. Check if there's a way to dump it with Odin. You can google around to see if it's possible but I'm pretty sure it's a feature in Odin (Whether our phone supports it is another story). You would have to boot into download mode, (vol down + home + power when powering on) and then follow whatever directions you find for dumping a rom. Just make sure you don't flash anything to your device. And make sure you know what you're doing with Odin because it can brick your phone if you push the wrong buttons.

2. The other way to do it is to dump your partition contents with the dd command (I would do it through an adb shell). This would require you to have root. I'm not sure of how to get root without modifying your ROM (kind of defeats the purpose of what you're trying to do if we have to change the ROM) but there are usually ways to get a temp root. Not sure how to do it on our phone but maybe someone else can help you with that part. Or maybe do some googling. The dd part I've at least done for the boot partition. Basically what you want to do is open an adb shell and run:

"ls -l /dev/block/platform/msm_sdcc.1/by-name/"

This will give you a list of all the partition name symlinks and show you the block devices they point to. For example, when I was getting boot.img I found that the "boot" symlink pointed to "/dev/block/mmcblk0p7". Find all the partitions you want to image in this list and figure out which block devices they point to.

The next part is to figure out how big each of the partitions is. You can find this in /proc/partitions. So from your adb shell you would run:

"cat /proc/partitions"

This will print out all of your flash block devices (look at the ones you were interested in from above). The 3rd column in this list will be the # of blocks in the partition. I believe the block size is 1k (1024 bytes). For example, my boot partition was 10240 blocks which comes out to 10 Megs, which sounds about right. The 1k assumption also agrees with the total device flash size, which is 7634944 blocks (mmcblk0) which is just under the 8GB they say the phone has. So I'm pretty confident about the block size.

So now we're at the part where things get a little hairy. I'm assuming you've found some way to get root in your adb shell. Be very careful with these dd commands and if you don't know what you're doing, don't do it. You would want to run something like the following:

"dd if=/dev/block/<partition name> of=/storage/sdCard/<name of image file> bs=1024 count=<# of blocks for partition you found in /proc/partions>"

You would do this for each partition you want dumped.

Again, be careful if you decide to try and do any of this stuff (especially with the dd commands, if you mix up the in file and out file you can brick your device). But like I said this worked for me to get boot.img and I was able to extract it and get the kernel and ramdisk. Hope this helps and sorry I don't know more about getting you a temp root without modifying your ROM.

20th January 2014, 06:28 AM |#3  
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20th July 2014, 02:58 PM |#4  
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hello everyone,
i resurrection this thread so bring some information to pepole who want to backup stock rom so they can flash it back with odin.

i constructed a list of partitions names/partition location nb./partition block size for a refreance of what to backup:

block size partition block location partition name

7634944 /dev/block/mmcblk0 Whole SSD on Device
2048 /dev/block/mmcblk0p5 aboot
6144 /dev/block/mmcblk0p20 backup
10240 /dev/block/mmcblk0p7 boot
860160 /dev/block/mmcblk0p17 cache
13952 /dev/block/mmcblk0p11 efs
10240 /dev/block/mmcblk0p19 fota
3072 /dev/block/mmcblk0p21 fsg
5120 /dev/block/mmcblk0p23 grow
61440 /dev/block/mmcblk0p1 modem
3072 /dev/block/mmcblk0p12 modemst1
3072 /dev/block/mmcblk0p13 modemst2
512 /dev/block/mmcblk0p9 pad
10240 /dev/block/mmcblk0p10 param
8192 /dev/block/mmcblk0p16 persist
10240 /dev/block/mmcblk0p18 recovery
512 /dev/block/mmcblk0p6 rpm
128 /dev/block/mmcblk0p2 sbl1
256 /dev/block/mmcblk0p3 sbl2
512 /dev/block/mmcblk0p4 sbl3
8 /dev/block/mmcblk0p22 ssd
1228800 /dev/block/mmcblk0p14 system
512 /dev/block/mmcblk0p8 tz
5386240 /dev/block/mmcblk0p15 userdata

so all you have to do is to use this command via terminal:
"dd if=/dev/block/<partition name> of=/storage/sdCard/<name of image file> bs=1024 count=<# of blocks for partition>"

you can cnange "sdCard" for "extSdCard" if you wish.

this will make you the raw imgae of all partitions and then you will need to use tar in linux to make a tar.md5 file for odin.
use the commands below in terimanl to do so:
"tar -H ustar -c image1 image2 image3 etc... > package_name.tar"
"md5sum -t package_name.tar >> package_name.tar"
"mv package_name.tar package_name.tar.md5"

remember you will need superuser on you phone to do this, also the commands are without the quotation mark.

the only thing left to know is what partitions you must backup to beable to restore fully to stock with/without data.
i know you should backup the boot/efs/recovery/system partitions for clean stock + userdata/cache if you want your data back.
does anybody know of other critical partitions to backup?
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