[LG Optimus 2x] spyrosk:
Dual Boot for P990 & SU660 on Both Bootloaders

Now with more and more new ROMs being released every day and only one phone (at least for most of us) to try them all, I think this was needed.​

It is based on the method Bihariel found on a Chinese forum and his latest v2 version for the old bootloader and my previous version 3 for the new one.

It is now modified to work on both bootloaders and Partition layouts. Read change log for details.

Thanks to:

SuperSkill personally, for digging it up from the grave and giving me the vote of confidence to port dual boot into the new bootloader. He is also the 1st after me, who tested it. (thank you again my friend)

KingMGT personally, for helping me make the necessary modifications for SU660 and of course for testing it since I don’t own a SU660. (thank you again my friend)

Bihariel of course, for his great work on which I based the new version (and for copying a lot of text from his thread)

ChinaGB, the creator of the System changer app and the original idea.

What is this useful for?

Devs: you can have one ROM configured and ready for use in one partition and a second partition to test your ROMs without touching your daily ROM, so you won/t need to wipe or backup anything.

Users: you can have a stable ROM, let’s say a stock ROM with everything working and configured and you can have a second partition to test ROMs (for example a custom stock based one or a CM10 beta) so you won't need to do backups and wipes.

How Dual Boot works?

Dual-Enabler.zip: this file enables Dual boot by splitting system partition into two.

Dual-ROM-1-to-XX.zip: this file have to be flashed after flashing ROM 1, after flashing it and boot the phone, you will find an app called system changer, by launching this app and selecting Switch ROM, the phone will reboot and start the ROM 2.

Dual-ROM-2-to-XX.zip: this file have to be flashed after flashing ROM 2, after flashing it and boot the phone, you will find an app called system changer, by launching this app and selecting Switch ROM, the phone will reboot and start the ROM 1.

What ROMs can I use?

P990 Devices:

You can use theoretically, any combination of ROMs for dual booting, working on the same Bootloader of course.

SU660 Devices:

On OLD layout you can use theoretically, any combination of ROMs for dual booting, working on this Bootloader of course.

On ICS layout, due to lack of any custom ROMs for SU660, the p990 layout and bootloader is used so only custom CM, PA & MIUI ROMs are compatible, working on this Bootloader of course.

Attention !!

The only ROMs you should not use are Auto-wipe ROMs because they will delete your data partition and with it ROM1 and ROM2 save files. Of course if you are an advanced user, you can open the wipe rom and modify the updater-script to remove the auto wipe lines.

Download from here the package for your device and follow the instructions in post #2.

For older versions follow the instructions included in package.

Change Log:

v5.0 Date 05 Feb 2013

DualBoot-Control.zip. All five zips used till now for enabling/maintaining Dual-Boot have been replaced by this aroma-style flash-able zip.

SU660 package now supports also the su660 ics bootloader & layout.

V4.6 Date 30 Jan 2013

512MB-512MB system partitions for both bootloaders,

Reduced data (to 2000MB) for old-bootloader (because a 2048MB one cannot be formatted on old bootloader)

Bug-fix for dual-boot remover (SystemChanger app wasn't removed).

V4.5 Date 22 Jan 2013

Now it auto enters recovery after repartitioning. No need to keep pressing Vol- & Pwr.

Linux nvflash binary added. (I had forgotten to include it in package, sorry.)

Minor changes in flash.sh (for linux).

V4 Date 20 Jan 2013

It now works on both bootloaders. During repartition with nvflash you have the option to select which one

In old bootloader the system partition is splitted in 370MB for ROM1 and 512MB for ROM2 (in case someone wants to install tonyp's & harsh's full ICS version for old bootloader).

Same simple procedure to enable and maintain dual-boot.

Common flash-able zips because they detect current bootloader and partition layout and act accordingly.

Re-compiled SystemChanger app to display more correct messages and also in which ROM you are switching to.

V3 Date 12 Jan 2013

System partition size is 512 MB for each ROM.

Data partition is still shared but with the max size of 2GB.

Included latest cwm recovery 6.0.2.5 by pengus77. It works for all available ROMs for new BL (DM X, FLEX-ICER & unofficial CM10 CM10.1 ones)

NewBL-Dual-Enabler’s scripts are modified not only for the new layout but now also check and format (if needed) the internal SD (the first time after NVFlash is always needed). It also returns to recovery automatically to let you install or restore the 1st ROM.

NewBL-Dual-ROM-1-to-XX.zip & NewBL-Dual-ROM-2-to-XX.zip no longer need to be updated with the boot images of the ROMs.

SystemChanger app’s scripts, before switching to the other ROM, check if current ROM is changed (by md5 checksum of its build.prop as before) and saves the boot.img for next switch.

noshare file, containing the data folders list, is now also saved under /data/dual-boot. This way it will be always accessible and updatable if needed, no matter which ROM is running.

Boot images and md5 checksums are also saved under /data/dual-boot.

Two more flash-able zips added:

Wipe-ROM-data.zip This will wipe the data of the current ROM. Useful for changing ROM or if required by ROM’s chef

Remove-DualBoot.zip This will wipe the data of the other ROM and will also remove the SystemChanger app and scripts from the current ROM. Useful if you want to make a clean nandroid backup, to restore after a repartition to normal layout.

For V2 change log see bihariel's thread