[Tutorial] How do not brick my phone upgrading ROM

[pax]

I’d like to create, with your help, a guide to upgrade ROM in our phone when we cannot find the exact one for our (chinese) telephon.

FIRST : BACKUP MY ROM
First of all we need a backup of our original ROM (with MtkDroidTools and SP_Flash_Tool, last version is important). Very important is scatter files, where I can understand the memory allocation of the various ROM component.

Backup also your IMEI with Root Explorer (I can find it in : /data/nvram/md/NVRAM/NVD_IMEI/MP0B_001) and with the specific function of Mobile Uncle Tools. Maybe useful to backup all /data folder…

SECOND : FIND A “PROBABLY” COMPATIBLE ROM
In my search I understood that critical are Baseband (radio part) and display resolution (graphic drivers in uboot.bin). While I found that is possible to tweak graphic drivers in uboot.bin, I didn’t understand how to tweak baseband (my is MAUI.11AMD.W12.22.SP.V5, but I can find tens of it with only the last Vx different…).

I downloaded a lot of possible compatible (for me…) ROM and the first verification was on the same scatter file. I choose only that I can flash with SP_Flash_Tool (no that .zip to upgrade with CWM).

Now a question : If the scatter is the same, is the ROM compatible and/or I don’t brick my phone ?

My idea is that I never wonna flash the original PRELOADER and DSP_BL. Is it enough ?

Must I add to them MBR, EBR1 and/or any of __NODL or other scatter file’s element ?

Here there is my scatter file :
PRELOADER 0x0
{
}
DSP_BL 0x40000
{
}
MBR 0x600000
{
}
EBR1 0x604000
{
}
__NODL_PMT 0x608000
{
}
__NODL_NVRAM 0xa08000
{
}
__NODL_SECCFG 0xf08000
{
}
UBOOT 0xf28000
{
}
BOOTIMG 0xf88000
{
}
RECOVERY 0x1588000
{
}
SEC_RO 0x1b88000
{
}
__NODL_MISC 0x2188000
{
}
LOGO 0x21e8000
{
}
__NODL_EXPDB 0x24e8000
{
}
ANDROID 0x26e8000
{
}
CACHE 0x227e8000
{
}
USRDATA 0x428e8000
{
}
__NODL_FAT 0x629e8000
{
}
__NODL_BMTPOOL 0xffff00a8
{
}

My idea is to try to flash with SP_Flash_Tool only : System.img (where is Android), Boot.img (where is the kernel). Is it a nonsense ?

So I could have the original uboot.bin (display and camera OK ?) and no problem with the boot of my phone (original Preloader, DSP_BL,MBR, etc).

But most important of all, I can restore my original files and resolve the possible brick of the phone. Am I right or wrong ?

Here you can help me to avoid errors and to understand better the problem

Now the last question : why I want to change my ROM ? The answer is because my faked Chinese Note2 clone works only in GSM/EDGE mode (I tested UMTS sim card…), the GPS is dead (I tried tweaks, soldered stripe antenna on the motherboard, modified gps.conf, etc.) and wifi is very slow…, so I hope in a ROM upgrade…

My last consideration on Chinese phone :

They are able to fake everything in the kernel writing all that they want (my is an original Samsung, the kernel version is 4.1.9?? (real 4.0.4), the resolution is 1280x720 (the real is 854x480), the hw is not Exynos but MTK 6577 and so on..). I tested it with CPUZ applet and for it is a genuine Samsung…, also Antutu make some mistakes..

So what about our privacy in the source code of this Chinese kernel/devices ? We haven’t source code so they can do all that they want…

Thanks all of you for every type of support to this post !

THANKS

[GizBeat]

Most scatters will be the same for the same chipset. However, I have seen some slight variations. Just because the scatter is the same doesn't mean the firmware is compatible.

Most definitely don't flash over the preloader when trying a firmware that isn't made for your phone.

Yes, always a good idea to backup IMEI with MobileUncle.

Flashing just system and boot is an okay idea. You can give it a try. Just make sure your original firmware is properly backed up.

Your issue with not having 3G could have to do with the phone not having a 3G radio. Inexpensive clones often don't have 3G radios.

I highly recommend you purchase a well known phone next time. I'm not trying to be mean, just trying to give some friendly advice.

[stevenma61]

i have seen a lot of chinese transplant other rom to their phone. it is quite difficult to do it in cable flash rom. they usually do it in card flash rom.

what u can try is back up yr rom by mtk droid tool. then create a cable flash rom from the backup, in case u soft brick yr phone. Then create a card flash rom from the mtk droid tool backup also. then try to modify the rom u download from the web with this card flash.

i never did it. but there is some tip to follow.
in the card flash rom. open the zip file, u see there r few folder, the driver for yr phone is under file folder .“lib”. so make sure that u have to keep this. delete the identical file in the rom that u download from the web, then copy yr original to the file folder“lib” and some of the driver is under “etc”.

i never did this before, i saw the chinese web site. they can transplant the rom in 2/3 hr for those who know the trick.

[pax]

Thanks Gizbeat & stevenma61

only few questions

>Just make sure your original firmware is properly backed up
I have MtkDroidTools and ReadBack ROM using SP FlashTool backup, is it enought ?

>I didn’t understand how to tweak baseband (my is MAUI.11AMD.W12.22.SP.V5, but I can find tens of it with only the last Vx different…).
Have you any advice ? In which file could it be ? Different Vx meaning different HW or only SW?

Where can I find "MBR, EBR1 and __NODL" information ?

If I have original System.img, Boot.img files can I restore my original files and resolve the possible brick of the phone if flashing other two of it have problems ?

What is a "cable flash rom " ?

>transplant other rom
I read something about it, but I see great problems with cut and paste... Expecially for me

I read somewhere that is impossible to find kernel sources for MKT 6577, isn't it ?

Thanks again for your support !

[stevenma61]

A ) To back up rom in case u brick yr phone

1- run the MTK droid root tool, hit the button "backup"
then u have a file folder name "AAA" (le me name it)

2 - Run the MTK root tool, then hit "to prepare blocks for Flash tool", then choose the file.md5 under thr folder "AAA", then let it run, after finish, u have a folder names "!Files_to_FlashTool" , then u have back up yr rom in SP flash tool format. in case u brick yr phone, this is the rom u are going to use with SP flash tool Version 3.1316 or new version. ( this is what I call cable flash rom)
note : during the above both process, u should not see any error message appear in the MTK droid root tool

B ) to transplant the rom from other phone to yr phone

1- run the MTK droid root tool, hit "to creat update for modified recovery", then choose the file.md5 from folder "AAA", after finish u have a folder "!Updates_to_Recovery", under that folder u have 4 to 6 zip file, the system.zip is the biggest size file, then this is the file u can install with when u are in CMW recovery. ( this is what I call card flash rom)

then u can start to modified this card flash rom with the card flash rom that u think are nearest to yr phone spec.