Android ROM (FirmWare) procedure backup&restore

I got several samsung mobile phones, and as tech as I got in the android EcoSystem -- is using samsung kies, or some apps filemanagement on the mobile phones.

Now, after one of my mobile phone got stuck while loading the system (to say exactly what happened -- is that for somereason after something was ran in the device -- I do not know whether it was a firmware update or something else -- the mobile loads and get stuck on the samsung logo)

None of the mobiles I got is rooted. And all the apps are -- as far as I know -- valid and none intrusive.

I been trying to figure out the following, in order to backup/restore Firmware/ROM:
A. Is a FirmWare (as samsung call it) is a ROM?
B. What is the procedure backing up a ROM from existing mobile device. Do I have to have root access to the device, or can it be preformed with a simple app.
C. What is the procedure restoring ROM.
D. Where can I get official Samsung FirmWare/ROMS for my mobile devices, and save them as files for later use? (I read on the web, that while the samsung Kies download the official ROM from their site -- it saves it in a temp dir, but doesn't save it for later use)....
E. What tools/procedure do I need -- in order to preform BackUp/Restore of ROMS?
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The exact answers to your questions varies depending on the exact device.

A. Yes. What samsung calls "firmware", is actually the ROM.

For the rest of your questions, I first have to explain a bit about the design of of an Android device:

In stock android, the operating system itself (the ROM) is mounted read-only and is NEVER touched by the device while booting, running, etc.. All user settings, apps, preferences, data etc. is stored in the /data and /cache partitions.

As an end-user, you never have to touch the ROM, or worry about it. There is nothing you can do from within the device that can modify this part of the system. Worst case scenario if your device is sufficiently messed up, you wipe the /data and /cache partitions and your device is reverted back to exactly how it was out of the box. This is what happens when you "reset to factory defaults" in the settings on the phone.

To backup your device, you don't actually backup the ROM. Instead, programs like Samsung Kies just makes backups of the general metadata on the /data partition - for example, the contacts, calendars, settings, phone logs, ringtones, memos, etc. on the device. This information is stored in a proprietary format, and can be restored using the Kies Software

There's also lots of other third party Apps which do exactly the same thing, saving the data onto the SD card. For example, GO Backup (

This is not a backup of the ROM. It's a backup of the Data. We assume the ROM is prestine and untouchable, and therefore doesn't need to be backed up.


If the phone won't boot for some reason (such as the scenario you described), on a stock phone the only reason is that something in the /data or /cache partition is causing the phone to crash.

Android phones have a separate small partition called the "recovery" partition, which is a separate little operating system which can be booted to and used to perform operations on the system ROM. Think of this like a "rescue CD" for your android device.

Steps to get into "recovery" mode varies from device to device, but usually involves holding Power+VOL UP while booting the device.

The OEM recovery shipped with most Samsung devices is very primitive, all it can really do is wipe the /data and /cache partitions and reboot the device. For most customers, that's all that is needed.  After all, if you assume the ROM is pristine and untouchable, anything that could have gone wrong on the device must have happened in the /data or /cache partitions.

^^^ This is what you should try and do, with your phone that isn't working, assuming it is not rooted and running the stock rom.

Unofficially, a rooted phone is capable of accessing the system partition, and all bets are off. If your phone damages the system partition (the ROM), you will need to flash it again from Recovery or Download mode. A custom recovery installed like Clockworkmod Recovery, provides far more functionality for doing this.


If you can't get into Recovery, Samsung devices have one final mode "Download Mode". This is a small program physically burned onto the device. It is extremely primitive, and can only communicate with proprietary Samsung tools installed on the PC and connected over USB, with appropriate drivers installed.

Samsung Kies is capable of talking to your device while it is in Download Mode. Samsung will use this mode to upload a new ROM (e.g. upgrade the firmware) on your device. In a stock environment, Samsung handles finding and downloading the latest, correct ROM. It's not your responsibility to do anything otherwise.


Now, if you actually want to be able to touch the ROM itself and do things like backups, flashing custom ROMs, etc, you need to install a custom recovery on your device which lets you access those parts of the phone.

Typically, you put a Custom Recovery onto your device through Download Mode. Samsung has a tool called "ODIN" which facilitates this, and an open source community tool called "Heimdall" works in a similar way. These tools let you flash a custom recovery onto the device - such as Clockworkmod Recovery.

It also voids your warranty. You're on your own now.


Now lets say you had Clockworkmod Recovery installed on the device, you could boot into recovery (generally by holding Power + VOL UP), and then access the advanced tools in ClockworkMod Recovery.

One of those tools Clockworkmod Recovery provides is to make a backup image of all the system partitions and saves it as a ZIP to the SD card. It can also restore a ZIP.

This is called a NANDROID BACKUP, and is the generally accepted standard practice for backing up and restoring your ROM.


Restoring your stock ROM onto a device means you need to possess that ROM. Either you had to have made a backup of it using Clockworkmod, or you need to download it.

The exact steps varies from device to device. Guides exist out there on forums like, and are usually called "unrooting and flash stock ROM on Samsung XXXXX device".

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Wow that was a long answer... okay here's the short version:

On an unrooted, stock samsung ROM, you don't backup the ROM and you're not supposed to worry about it.

The ROM is untouchable by the apps on the system, it is mounted as read-only when the device is running. It is therefore (theoretically) impossible for an app running on the phone to damage or change the ROM itself.

All of the data - apps, settings, EVERYTHING, that you do to the phone after you get it out of the box, is saved in the /data and /cache partitions on the device, which is stored separately from the ROM itself.

Any problems you experience on the phone can only be a result of bad information in the /data and /cache partitions. And it can be fixed by wiping the phone to factory defaults.

You can do it two different ways:

1) Under Settings, while the device is running, there is an option to wipe and reset the device

2) If the device won't boot (e.g. hanging on the samsung logo like you said), you can instead boot into "recovery" mode where you can wipe to factory defaults. Recovery mode varies from one device to the next, but generally with Samsung devices you boot the device while holding POWER + VOL UP, and you're presented with a menu, one of the options is to wipe the device to factory defaults. You use the volume up/down and power buttons to navigate the menu.

If these things don't work, or for whatever reason you actually do want to re-install a ROM onto the phone you do so using "Download Mode" and the Samsung Kies application. Kies will download the appropriate ROM from Samsung, and you don't have much control over the process.
amitbuenoAuthor Commented:
Excellent answers... It put a lot into perspective, yet, I would like to pinpoint the exact situation I am in:

* My device won't boot into android os
* I've, even before the post, did a wipe data/ cache/ -- yet it didn't result with anything on my device.
* I did get into "Download" mode and tried to run on KIES the "Tools/Firmware upgrade and initialization" -- I've entered in the procedure my mobile brand and the S/N -- yet, it failed with an "Failed to run firmware upgrade. Unknown error occurred."

! How can I overcome KIES from presenting that error --? I believe that reinstalling (even the same Firmware I got) would fix the load problem.

* I bought the same brand of samsung mobile to my mum as well.
* When in "Download" Mode -- it specifies the following "Custom Binary Download:"
-- On my phone the value was "Yes (1)"
-- On my mum phone the value was "No"
? What does that mean, I am guessing that that is one of the reason my mobile crashed for the second time, cause it was using a custom binary... It that reasonable to assume?
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Ahah - the "custom binary" flag when you're in Download Mode is a flag that is turned on by Samsung when it detects an attempt to upload a custom ROM or recovery onto the phone. Basically, if you attempt to root / upload a custom recovery or ROM your phone through Download Mode, this flag gets tripped and it voids your warranty.

So SOMEBODY at some point tried to root / upload a custom ROM or recovery to this phone.

This means you can no longer assume that the phone is stock, and you can no longer assume that the integrity of the ROM / recovery image have not been compromised.

My personal suggestion, is root the phone and go the custom-ROM route. Your customer will probably like Cyanogenmod or AOKP better than the stock ROM, and you don't have to fuss around with Samsung Kies (which, to be honest, is a piece of garbage).

So this means you'll be going into Download Mode, then use the Samsung ODIN tool or Heimdall suite to upload the applicable Clockworkmod Recovery image into the phone. Then, boot into recovery mode and upload the applicable ROM to your phone's SD card. Then, flash the applicable ROM zip file and the applicable GApps zip file in order to flash a custom ROM onto your phone.

So... what's the EXACT model no of the phone? (Find the precise model number under the battery) I can point you at the appropriate links where to download the various tools and ROMs and Images you need.
amitbuenoAuthor Commented:

* Is it possible to use an Official ROM after loading custom ROM?
* My phone model is GT-S6500D -- Tried looking for ROMs for that put didn't find any good links.
* In addition I do not know what does the ROM contains and whether to trust it? how do I check the packages of a ROM? and what do I need to check in it?
amitbuenoAuthor Commented:
Took me a while to grant the points, yet, the initial response was quite complete...
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