[LG Optimus 3D] berni987654321:
Hi guys,

finally I found a way to make dualboot on our beloved O3D working!!

This way isn't as much easy as on other devices like the desire HD where

you have just to install an app and everything is done by itself, so follow this

guide at your own risk!!

//Dualboot any rom and a cm10.1 based rom from external sdcard

Same as cm10 based but use the cm10.1.img

//Dualboot any and a cm10 based rom from external sdcard

Warning after following this guide your external sd card lost about 2gb!!!!

1. Make a backup of your external sdcard to your PC!! All your data on the sd card will be gone!

2. Reboot to cwm- or twrp-recovery (power+vol down+3d button)

3. connect your phone to your pc.

4, open up cmd or a terminal and type:

adb shell

(if your using twrp you can use the built in terminal)

5. type:

cd /dev/block
parted mmcblk1
print

on an 8gb sd it will show you something like this:

6. type:

rm 1

all you data on the sdcard is now gone.

7. type:

mkpartfs primary fat32 1049kb 6000mb //instead of 1049 you have to enter the start that was told you by print and for 6000mb you have to enter your end minus 2 gb (my end is 8051mb - 2gb(=2000mb) ~ 6000mb

mkpartfs primary ext2 6000mb 6700mb //the end of your first partition (for me 6000mb) + 700mb = 6700mb

mkpartfs primary ext2 6700mb 7900mb //the end of your second partition (for me 6700mb) + 1200mb =

mkpartfs primary ext2 7900mb 8051mb //the end of your third partition and the end that parted told you after entering print before modifying anything (8051mb)

8. type:

print

you should get something like this:

Disk /dev/block/mmcblk1: 8051MB

Sector size (logical/physical): 512B/512B

Partition Table: msdos

9. type

quit

and turn off your phone and boot again to recovery

10. type on pc:

adb shell
mke2fs /dev/block/mmcblk1p2
tune2fs -j /dev/block/mmcblk1p2
mke2fs /dev/block/mmcblk1p3
tune2fs -j /dev/block/mmcblk1p3
mke2fs /dev/block/mmcblk1p4
tune2fs -j /dev/block/mmcblk1p4

Now you have 3 new partitions for data2 system2 and cache2.

The first part is done.

Now we have to edit the updater-script to make it install the system and maybe the data on our new partitions.

Open the updater-script of your jb based rom(for my pac man rom there is no need to cause I'll upload a versions for int and one for ext sd)

1. Open the zip you want to install as second rom with winrar or something like this.

2. Open the updater-scrip in the zip and change all the mmcblk0p7 to mmcblk1p2 and mmcblk0p8 to mmcblk1p3.

Flash your rom but stay in recovery

Now we have to change the boot.img in the zip to modivied one, just flash one of the zips that suits to your ROM

OK last step is to edit the gapps to be flashed on second ROM:

Just open the updater-script and change the line busybox mount system line to

mount("ext4", "EMMC", "/dev/block/mmcblk1p2", "/system");

And save it

//Dualboot a stock gingerbread based rom and a cm7 based rom from internal sdcard

Warning after following this guide your internal sd card is only 3545mb big!!!!

Here is a tool that makes all the work for you credits to defcomk:

http://d-h.st/hux

1. Make a backup of your internal sdcard to your PC!! All your data on the sd card will be gone!

2. Reboot to cwm- or twrp-recovery (power+vol down+3d button)

3. connect your phone to your pc.

4, open up cmd or a terminal and type:

adb shell

(if your using twrp you can use the built in terminal)

5. type:

cd /dev/block
parted mmcblk0
print

it will show you something like this:

Number Start End Size File system Name Flags

1 131kB 262kB 131kB x-loader

2 262kB 393kB 131kB nv1

3 393kB 524kB 131kB nv2

4 524kB 1049kB 524kB u-boot

5 1049kB 11.5MB 10.5MB kernel

6 11.5MB 22.0MB 10.5MB recovery

7 22.0MB 651MB 629MB ext4 system

8 651MB 1725MB 1074MB ext4 userdata

9 1725MB 1859MB 134MB fsswap

10 1859MB 1926MB 67.1MB ext3 cache

11 1926MB 1928MB 2097kB ext3 lgdrm

12 1928MB 1929MB 1049kB divxkey

13 1929MB 1950MB 21.0MB fota

14 1950MB 1955MB 4194kB ext3 misc

15 1955MB 7944MB 5987MB fat32 fat

6. type:

rm 15

all you data on the sdcard is now gone.

7. type:

mkpartfs primary fat32 1955 5500
mkpartfs primary ext2 5500 6100
mkpartfs primary ext2 6100 6200
mkpartfs primary ext2 6200 7944

8. type:

quit

9. turn off your phone and boot again to recovery

10. type on pc:

adb shell
mke2fs /dev/block/mmcblk0p16
tune2fs -j /dev/block/mmcblk0p16
mke2fs /dev/block/mmcblk0p17
tune2fs -j /dev/block/mmcblk0p17
mke2fs /dev/block/mmcblk0p18
tune2fs -j /dev/block/mmcblk0p18

Now you have 3 new partitions for data2 system2 and cache2.

The first part is done.

Now we have to edit the updater-script to make it install the system and maybe the data on our new partitions.

1. Open the zip you want to install as second rom with winrar or something like this.

2. Open the updater-scrip in the zip and change all the mmcblk0p7 to mmcblk0p16 and mmcblk0p8 to mmcblk0p18.

Now we have to change the boot.img in the zip to modivied one, just flash one of the zips that suits to your ROM

After flashing the zip you will boot into the second rom you have installed, to boot back to the first rom you will have to flash

a boot.img that suits to your rom (for stock rom something like the Promethius Kernel)

On stock roms it could happen that your sdcard isn't mounted correctly

you can try to change the vold.fstab in /system/etc to something like :

There are some great tools here

//For Kernel Devs Create your own DualBoot image

I wanted to see some more dualboot kernels and I don't have time to create the b myself so I made this tool.

Just extract it, put a kernel in the put_zImage_here folder and start the tool. For now there is only 4.1.2 but

4.2.2 will be added soon.

You can post the image in your kernel thread, and if you want you can send me a PM to add a link to the kernel

Please post any trouble.