[Q] I9300XXELLA downgrade and other questions

Search This thread

Vinceee

Member
Nov 12, 2013
20
1
Hi everyone,

Before I flash a custom rom, I would like to know the answer to some questions I have.
This is the situation: I have an international galaxy s3, I9300XXELLA, with stock rom and android 4.1.2 and I'm interested in flashing the latest cyanogenmod 11 milestone.

I would make a nandroid backup first, so will I be able to just flash my nandroid of version 4.1.2 and downgrade from android version 4.4.2 to 4.1.2?
Also, if I make a nandroid of cyanogenmod 11, will I be able to just switch between the two roms like it's nothing?

Sorry if my questions are noob, but I've tried to downgrade before and I got stuck in a bootloop, I don't want to get this problem again..
And yes, I've searched google.

Any help is greatly appreciated!
 

Jumaqidi

Senior Member
Dec 3, 2013
1,099
190
Hi everyone,

Before I flash a custom rom, I would like to know the answer to some questions I have.
This is the situation: I have an international galaxy s3, I9300XXELLA, with stock rom and android 4.1.2 and I'm interested in flashing the latest cyanogenmod 11 milestone.

I would make a nandroid backup first, so will I be able to just flash my nandroid of version 4.1.2 and downgrade from android version 4.4.2 to 4.1.2?
Also, if I make a nandroid of cyanogenmod 11, will I be able to just switch between the two roms like it's nothing?

Sorry if my questions are noob, but I've tried to downgrade before and I got stuck in a bootloop, I don't want to get this problem again..
And yes, I've searched google.

Any help is greatly appreciated!
U cant switch like its nth. Whenever u go from cm11 to stock 4.1.2, u have to restore ur efs v1. Wat modem are u using atm?

Sent from my SM-N9005 using xda app-developers app
 

JJEgan

Senior Member
Oct 24, 2010
30,509
5,923
Samsung Galaxy Note 3
The above post is absolutely wrong. Custom ROMS including CM never include a modem in the RO

Wrong wrong wrong custom roms may and indeed do include a modem or even a choice of modems . Fairly obvious from reading rom descriptions .Modem: BUUGMJ3 Modem: XXUGMK6
Modem:
- XXEMG4
- BUUGMJ3
- XXUGMJ9
- XXUGMK6
- DDUGMK1
 
Last edited:
  • Like
Reactions: thadoukuki

tallman43

Senior Member
Aug 29, 2011
1,721
638
The Land of Android
  • Like
Reactions: Vinceee

thadoukuki

Senior Member
Aug 17, 2012
280
48
The above post is absolutely wrong. Custom ROMS including CM never include a modem in the RO

Wrong wrong wrong custom roms may and indeed do include a modem or even a choice of modems . Fairly obvious from reading rom descriptions .Modem: BUUGMJ3 Modem: XXUGMK6
Modem:
- XXEMG4
- BUUGMJ3
- XXUGMJ9
- XXUGMK6
- DDUGMK1

Extract CM ROM zip and see for yourself if it includes a modem or not.

Sent from my GT-I9300 using XDA Premium 4 mobile app
 

Vinceee

Member
Nov 12, 2013
20
1
Also do not flash any roms untill you know what efs is and how to back it up! not doing so may lead to a unusable phone read this >> http://xdaforums.com/showthread.php?t=2393289 << and post any questions regarding efs in the thread.

Okay I've read the topic about efs and IMEI, but I'm not sure if I understand everything correctly
Please correct me if I'm wrong and feel free to give extra information, this is what I think I understand:

  • Once I flash a rom that was made after the efs format change, I can't go back to a previous version of my modem on that rom.
    If I make an efs backup with CWM, I CAN restore it only if I go back to my stock android 4.1.2 (?)

But do I need to restore my efs backup on my new rom? I thought that wasn't necessary..

And another thing, I already succesfully installed a PA version AFTER the format change (I think android 4.3), and was able to go back to stock 4.1.2.. Got a bootloop but was able to fix that in recovery. The stock rom still works, never had problems with the modem what so ever, the only thing I did was restore my nandroid backup of 4.1.2, fixed the bootloop in recovery, and got a working, factory resetted 4.1.2...


So if I flash CM11, will I be able to go back to stock if I use a nandroid (and efs) backup?
Can someone give me a step by step tutorial please? (I just want to know what I have to do)
 

Jumaqidi

Senior Member
Dec 3, 2013
1,099
190
Then please let me know where to find it, because I can't seem to find a code that ends in a number at 'about phone'

Baseband version.

Sent from my GT-I9300 using xda app-developers app

---------- Post added at 07:56 AM ---------- Previous post was at 07:54 AM ----------

Btw. U can switch nandroids between stock and cm 11. But rmb to factory reset then restore nandroid.

Sent from my GT-I9300 using xda app-developers app
 

Vinceee

Member
Nov 12, 2013
20
1
Baseband version.

Sent from my GT-I9300 using xda app-developers app

---------- Post added at 07:56 AM ---------- Previous post was at 07:54 AM ----------

Btw. U can switch nandroids between stock and cm 11. But rmb to factory reset then restore nandroid.

Sent from my GT-I9300 using xda app-developers app

It says I9300XXELLA like I told you before..
I can take a screenshot if you don't believe me
 

Vinceee

Member
Nov 12, 2013
20
1
Okay. But like I said. U can switch between nandroids. Just factory reset before each restore.

Sent from my GT-I9300 using xda app-developers app

Thanks, so I don't have to worry about the modems or the efs? Even though my build version is from before MG2?
So for switching to CM and back to stock, I should do:
- make a titanium backup of apps
- make nandroid backup of 4.1.2
- factory reset/wipe cache/wipe dalvik cache
- flash CM
- factory reset/wipe cache/wipe dalvik cache
- (test CM rom, put on some apps ect.)
- make nandroid backup of 4.4.2
- factory reset/wipe cache/wipe dalvik cache
- flash nandroid of 4.1.2
- factory reset/wipe cache/wipe dalvik cache
- reboot
- restore apps with titanium backup

Will this work?
Thanks everyone, any help is welcome
 

Jumaqidi

Senior Member
Dec 3, 2013
1,099
190
Thanks, so I don't have to worry about the modems or the efs? Even though my build version is from before MG2?
So for switching to CM and back to stock, I should do:
- make a titanium backup of apps
- make nandroid backup of 4.1.2
- factory reset/wipe cache/wipe dalvik cache
- flash CM
- factory reset/wipe cache/wipe dalvik cache
- (test CM rom, put on some apps ect.)
- make nandroid backup of 4.4.2
- factory reset/wipe cache/wipe dalvik cache
- flash nandroid of 4.1.2
- factory reset/wipe cache/wipe dalvik cache
- reboot
- restore apps with titanium backup

Will this work?
Thanks everyone, any help is welcome

Restore BEFORE. No nid for AFTER.

Sent from my GT-I9300 using xda app-developers app
 
  • Like
Reactions: Vinceee

tallman43

Senior Member
Aug 29, 2011
1,721
638
The Land of Android
Yes you do have to worry about efs if you do not backup your efs you may have problems maybe not today or in a week or month but if you ever corrupt your efs by flashing roms and you do not have a backup you will have big problems!....First rule when flashing roms backup efs! :)
 
  • Like
Reactions: Vinceee

Vinceee

Member
Nov 12, 2013
20
1
Restore BEFORE. No nid for AFTER.

Sent from my GT-I9300 using xda app-developers app

So can you give me the right steps please? You can just edit my post in a quote or something, thanks :)
And like that I can perfectly switch between roms, right? No problems with efs (if it doesn't get corrupted by accident)?
 

Jumaqidi

Senior Member
Dec 3, 2013
1,099
190
- make nandroid backup of 4.1.2
- factory reset/wipe cache/wipe dalvik cache
- flash CM
- (test CM rom, put on some apps ect.)
- make nandroid backup of 4.4.2
- factory reset/wipe cache/wipe dalvik cache
- flash nandroid of 4.1.2
- reboot

Dun nid to back up the apps since nandroids do back up them alr. Save the nandroids to ext sd card. Recommend 16 or 32 gb sd card for this. And backup efs to ext sd card too. IMPORTANT TO BACKUP EFS


Sent from my SM-N9005 using xda app-developers app
 

Top Liked Posts

  • There are no posts matching your filters.
  • 1
    U cant switch like its nth. Whenever u go from cm11 to stock 4.1.2, u have to restore ur efs v1. Wat modem are u using atm?

    Sent from my SM-N9005 using xda app-developers app

    I'm sorry isn't my modem the XXELLA I already gave?
    And how do I restore my efs v1 then, and what is it?

    Thanks :)
    1
    The above post is absolutely wrong. Custom ROMS including CM never include a modem in the RO

    Wrong wrong wrong custom roms may and indeed do include a modem or even a choice of modems . Fairly obvious from reading rom descriptions .Modem: BUUGMJ3 Modem: XXUGMK6
    Modem:
    - XXEMG4
    - BUUGMJ3
    - XXUGMJ9
    - XXUGMK6
    - DDUGMK1
    1
    I'm sorry isn't my modem the XXELLA I already gave?
    And how do I restore my efs v1 then, and what is it?

    Thanks :)

    Also do not flash any roms untill you know what efs is and how to back it up! not doing so may lead to a unusable phone read this >> http://xdaforums.com/showthread.php?t=2393289 << and post any questions regarding efs in the thread.
    1
    It says I9300XXELLA like I told you before..
    I can take a screenshot if you don't believe me

    Okay. But like I said. U can switch between nandroids. Just factory reset before each restore.

    Sent from my GT-I9300 using xda app-developers app
    1
    Thanks, so I don't have to worry about the modems or the efs? Even though my build version is from before MG2?
    So for switching to CM and back to stock, I should do:
    - make a titanium backup of apps
    - make nandroid backup of 4.1.2
    - factory reset/wipe cache/wipe dalvik cache
    - flash CM
    - factory reset/wipe cache/wipe dalvik cache
    - (test CM rom, put on some apps ect.)
    - make nandroid backup of 4.4.2
    - factory reset/wipe cache/wipe dalvik cache
    - flash nandroid of 4.1.2
    - factory reset/wipe cache/wipe dalvik cache
    - reboot
    - restore apps with titanium backup

    Will this work?
    Thanks everyone, any help is welcome

    Restore BEFORE. No nid for AFTER.

    Sent from my GT-I9300 using xda app-developers app