yashsingh1/xdaforums huggingface dataset:
[LG Optimus 3D] Bdadd34:
Yes you need to keep a cwm install zip for each rom and just boot to recovery flash kernel and reboot then the rom will boot. Remember rom2 needs modified boot.img made by bernie. Just use your favorite kernel for rom1.
[LG Optimus 3D] eternal.sumit:
thanx Bdadd34

"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)".What does this mean how to flash boot.img,does this mean flashing kernel of first ROM to boot into it.We need to flash modified boot.img(kernel) by bernie to boot 2nd ROM,is it?and to switch between each corresponding ROM we need to flash each time kernel of that specific ROM,is it so?
[LG Optimus 3D] berni987654321:
Yes
[LG Optimus 3D] eternal.sumit:
In case we need to undo Dual boot,what should we do??:)
[LG Optimus 3D] berni987654321:
Enter recovery, open mmcblk0 with parted, delete partition 16 16 17 18 and make a new fat 32 partition
[LG Optimus 3D] fabersantucci:
dual boot is possibile on ics ?? CM9 & Stock 4.0.4
[LG Optimus 3D] berni987654321:
Yes but it would need some changes and there would problems with the int SD card cause it is with ice only 5gig. Maybe this weekend I'll take a look on it
[LG Optimus 3D] lzzar:
Can I dual boot stock 21a and cm10? That would be awesome cause then the memory would be as usual and if , I wanted 3d functions during the day when I'm on cm10 I could just dual boot to stock ROM!!

Sent from my 3D phone.
[LG Optimus 3D] berni987654321:
Yes that's possible but I'll have to make a new boot.img
[LG Optimus 3D] lzzar:
Could you please? I dont know if that is like asking for etas?

Sent from my 3D phone.
[LG Optimus 3D] berni987654321:
no prob im just a bit in trouble now cause my phone has problems with downgrading to gb, my win 8 won't boot beacuse my hdd goes crazy and my laptop is lame as hell so I have not much time
[LG Optimus 3D] lzzar:
Haha ok

Sent from my 3D phone.
[LG Optimus 3D] lzzar:
What exactly is it that you do with the boot.img ? If it is not too hard maybe I can try it myself. :)

Also. Does it matter which ROM you have on the sdcard? In terms of speed I mean, is the partition made for the system faster then the one we are creating from the internal sdcard?

Sent from my 3D phone.
[LG Optimus 3D] herogjan:
I'm tryining this now for two days, but i can't manage this to get working. The automated script doesn't work for me (somehow i always press the wrong button), so i do it manually. Which is fine by me.

I'm suceeding in making room for 2 roms, but when i install the second rom it fails. Resulting in several semi bricks (thanks wkpark for the tool), but i'm no at the point were i ask for a litlle help. When i install the second rom with the replaced .img file from bernie and the altered update script. I get always the error message unable to mount cache, i tried everything what i can think, such as reformat sd, reformat cache (auto and parted) mounting trough recovery, all not working. When i then reflash first rom system and data also not mounting anymore.

So i flashed a lot these days, at this moment i erased the whole thing trough parted, except kernel, boot, recovery ,nv1, nv 2, x-loader and u-boot. So it's now receiving new rom trough lg official tool, but i still want dualboot.

I noticed that cache is shared by this two roms, and somehow whiping before install is not working. Is it an idea to also create a second a second cache for second the second rom? It can adjusted in the update script, i don't now of the boot.img needs an adjustment (somehow i'm also not succesfull in extracting these ones)

So what for problems did you guys ran into, and how did you solve?

I tried for first stock v21b, v21, dna333, prometeus, and second cm7, cm10, dna333, prometheus.
[LG Optimus 3D] berni987654321:
For second you can only use cm based ROMs yet
[LG Optimus 3D] herogjan:
Ok, thanks. Will try again. Just to know for sure, i can install cm10 and cmy7?

In your guide you create 3 partitions, data system and cache. But you reroute in the 2nd rom only two.

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

the cache isn't rerouted above, is it an option to also reroute mmcblk0p10 tommcblk0p17?
[LG Optimus 3D] berni987654321:
In update script is nothing about cache cause I don't know any ROM which flashes to cache partition but 1st and 2nd ROM use different cache partitions. Cm10 as 1st ROM and cm7 2nd shall work
[LG Optimus 3D] biolo:
Now i deletet partition and instal 2 rom but i have stock v21a and second i instal stable cyanogenmod from http://download.cyanogenmod.com/?type=stable&device=p920

but can not be loaded :(

What can I do to get it working?
[LG Optimus 3D] berni987654321:
just dualbooted my pacman rom with an older version of it from ext sd card will ad tomorrow how to

Dualboot gingerbread ROM and jb rom shall work too if the baseband is the same
[LG Optimus 3D] herogjan:
Very nice, looking forward to it.
[LG Optimus 3D] biolo:
Litle help please

2 rom is cm beta

I trying instal 2 rom but always instalation stop in 50%~60% :( i create update-script but i shuld add boot.img from berini zip (kernel) to cm rom??

if i instal normal cm work good but i can't instal it a 2 rom :(
[LG Optimus 3D] biolo:
Hi where is your pac man boot.img for ex-sd??

I finally instal yours pac man ROM but i don't have boot.img for this 2 rom :(
[LG Optimus 3D] berni987654321:
Sorry but i had some trouble the last days but it wont take much time for me now to upload it
[LG Optimus 3D] berni987654321:
pacman and cm10 are online didn't tryed cm10 but should work
[LG Optimus 3D] Chris189:
Hi Berni! Thanks for your work! I like ask a question, i have Acura rom and i like my second rom , jellybam. If i flash the CM10 pac kernel it will work or i need a modified jellybam kernel? Thanks

Sorry for my bad english
[LG Optimus 3D] berni987654321:
Didnt test it with jellybam but shall work
[LG Optimus 3D] Chris189:
Thanks for the info :) And one more question if u don't mind. Are there any differences between the CM kernel you uploaded and the Stock Jellybam kernel?
[LG Optimus 3D] berni987654321:
The kernel in mz boot.IMG and the boot.IMG in the jellybam ROM are the same but there are changes in the ramdisk of my boot.img
[LG Optimus 3D] Chris189:
I installed JellyBam 3.2.0 and my custom 2.3.5 rom and its working great , and your CM10 kernel is working fine with JellyBam. Thank you Berni!
[LG Optimus 3D] biolo:
Thanks Berni

Finally works for me stock gb 2.3.5 and you 4.1.2 pac man rom :))

but When will switch to 4.1.2 i have 2 reboots and everything works well

This is the problem with reading IME the third (boot) time is ok for me :))

Chris189 good to know the work JB 4.2.0 :))

thanks to all

I finally have Dual Boot :))
[LG Optimus 3D] berni987654321:
Thanks its good to know
[LG Optimus 3D] lzzar:
I dont have a that fast ex sdcard. Can you maybe make an boot.img that installs in the phone partition like dualbooting gb?
[LG Optimus 3D] berni987654321:
Maybe I'll make one but there will be problems with mounting int sd
[LG Optimus 3D] berni987654321:
P.s I have a pretty cheap SD card and it is smooth enough in my opinion
[LG Optimus 3D] biolo:
Confirm :)

I have "no name" 4GB sd card and work good :)
[LG Optimus 3D] eternal.sumit:
what about CM 10 and stock GB ROM?

can we dualboot CM 10 and stock GB ROM using this method???:confused:
[LG Optimus 3D] svprm:
Currently i'm on GB V21E.

Then i setup your Dualboot method.

Installed the CM 10.

Then i flashed Original_cm kernel from this thread.

It showed me a black screen.

Then i flashed Cm10_pac kernel.

CM 10 booted successfully.

But after a few minutes,it get rebooted.

Don't know why?
[LG Optimus 3D] Chris189:
Berni: Can you convert the MIUI kernel or Iodak CM10 kernel to boot from the internal SD card ? it would be really awesome :)
[LG Optimus 3D] berni987654321:
Most likely yes
[LG Optimus 3D] Chris189:
If you have time can you do convert please ? The partition creation and etc i can do it easly but i can't modify the kernel, i don't know much about it.
[LG Optimus 3D] berni987654321:
Maybe I have tomorrow time but that's not an ETA nor a promise that I'll do it
[LG Optimus 3D] Chris189:
I understand , and im sorry to bother you with my things. Many thanks :)
[LG Optimus 3D] biolo:
hi berni

You can call on 4.1.2??

I can't call but i have signal :/
[LG Optimus 3D] lzzar:
when i am trying to make the second partition the phone reboots. Am i the only one?
[LG Optimus 3D] berni987654321:
when does it happen?

you're in recovery mode and type in adb "rm 1"?

don't have any problems with calling people,

what exactly happens when you try to call sb?
[LG Optimus 3D] lzzar:
ok i fixed it. I downzised the first partition a 100mb and it worked!

I have installed your PACman and its working fine on sdcard. Should a flash prometheus kernel to dualboot to stock v21a?
[LG Optimus 3D] berni987654321:
no you have to flash a v21a based kernel maybe an old version of titan kernel or stock v21a kernel
[LG Optimus 3D] lzzar:
Noticed that. I flashed prometheus 1.5+ and it had no signal so I flashed 1.2+ and it had signal! So now everything works!
[LG Optimus 3D] biolo:
When trying to call i hear connection can't be done ;/

I have baseband LGP920AT-00-V21e-EUR-XXX-APR-19-2012+0_CP

and This is the same as your??

OK I solved my problem instal JB v3.3.0 and everything working :)
[LG Optimus 3D] Smeagol44:
Hi guys, I'm really interested in doing this, but first I'd like to clafiry some doubts I have;

1) Can I have the Acura 3D Max rom as base one, and CM 10 for the 2nd rom ? (I'm on v20p baseband)

2) Should I use the automated script or should I do it manually? Which is better/safer ?

3) When doing this, will I have different kernels for the different systems? I'm using the Acura's kernel to OC @ 1.3GHz, and I would like to keep this on this rom. =)

Thanks in advance, guys !

(and pardon my english, not my native language)
[LG Optimus 3D] berni987654321:
To dualboot you ave to do it manually cause the script works only for gb roms. You can dualboot acura 3d max and cm10 but you will have the acura kernel and my cm10 kernel so you have 1.3ghz only at acura rom
[LG Optimus 3D] Smeagol44:
Awesome! As long as I have it on Acura's rom, that's fair enough to me.

Last question, Acura's Rom is a GB rom. That wouldn't go into conflict or something with CM10, right? (Being the last a JB rom)
[LG Optimus 3D] berni987654321:
I dualbooted stock gb and cm10 without any problm
[LG Optimus 3D] Smeagol44:
Ah, ok. Thanks.

One more 'last thing'. Wich boot.img should I use? Where do I get it?

Sorry if I'm being too annoying. It's just that I don't wan't to make things wrong. =)
[LG Optimus 3D] berni987654321:
To boot cm10 flash cm10_pac.zip attached in first post and for acura rom flash any gb kernel that works for you
[LG Optimus 3D] lzzar:
Could you maybe edit the custom kernels for CM10 on the development section for dual booting or maybe send me a pm with the things you have to edit in the init.rc so I can do it myself?

Maybe Peseach kernel?

Sent from my 3D phone.
[LG Optimus 3D] berni987654321:
Pesach ask me already some hours ago how to do it i think he'll be making soon one
[LG Optimus 3D] Smeagol44:
I'm having some troubles here. Where is this "updater-script" file? I found one in \META-INF\com\google\android\ of the CM10 zip, is this the one I need to modify?

Also, when i'm going to replace the "mmcblk0p8" for "mmcblk1p3" in this file, there's no "mmcblk0p8" to replace... Is this right? What am I doing wrong? =(

EDIT: I've just saw your post in reply to lzzar, my bad for not reading before. I guess i'm about to flash.. wish me luck! =D

EDIT 2:

Ok, one last request:

For the gapps file, is this the line I have to modify??

run_program("/sbin/busybox", "mount", "/system");

and how should it look like? Like this?:

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

???

Tottally lost here. =(
[LG Optimus 3D] berni987654321:
Its the right line you found, completly delete it and put just this in:

mount("ext4", "EMMC", "/dev/block/mmcblk1p2", "/system");
[LG Optimus 3D] Smeagol44:
Thanks Berni, now I'm having another issue with CM10 (Dual boot works flawlessly!!), I don't have signal, not IMEI neither data, etc. It's strange because first time I flashed CM10 to the SDcard it worked. Now it doesn't. =(

EDIT: Is it possible to flash CM7.2 over CM10 in the SDCard??
[LG Optimus 3D] berni987654321:
not from external sdcard like cm10 but you can triboot cm7 (following the second tutorial), cm10 and stock gb
[LG Optimus 3D] Smeagol44:
Hahaha you're awesome man. =)

Is there a way I can 'wipe' the CM10's partitions? (the ones in the SD) because I think I'm gonna try jellybam.
[LG Optimus 3D] berni987654321:
yes enter recovery and type

mke2fs -T ext4 /dev/block/mmcblk1p3

and

mke2fs -T ext4 /dev/block/mmcblk1p4
[LG Optimus 3D] Smeagol44:
Well Jellybam reboots after bootanimation. Don't know what did go wrong, I think I'll try reflashing.

@Chris189, did you just modified the updater-script and flashed it with the cm10_pac ??

If anyone that knows anything about this and can help, it would be appreciated.

---------- Post added at 02:11 PM ---------- Previous post was at 02:08 PM ----------

I once tried to flash ICS, and now that I remember, the 'download-mode' of my phone is still with those korean words. I think is is causing all my problems with CM10-based roms. I'll search how to return to the GB bootloader and see if it helps. Anyone have a link to a step-by-step or something?

Anyway, I'll search the forums..
[LG Optimus 3D] Chris189:
Yes I just modified the updater script then installed the modified kernel by Bernie. Flash v21e baseband files and Bernie's files if u have installed ICS rom.
[LG Optimus 3D] Smeagol44:
Shouldn't I flash v20p ? (my base rom is working fine, with imei, and v20p baseband, it's just that I still got the korean download-mode)
[LG Optimus 3D] androidos000:
is it possible to put GB custom rom on the 2nd partition while cm10 is in the first partition?
[LG Optimus 3D] Chris189:
Did you flash Berni downgrade files?
[LG Optimus 3D] Smeagol44:
What downgrade files? =(
[LG Optimus 3D] Chris189:
You need to flash this files if you had ICS installed on your phone before.

http://xdaforums.com/showthread.php?t=2037287&highlight=downgrade
[LG Optimus 3D] berni987654321:
Probably yes but it wouldn't make any change
[LG Optimus 3D] lzzar:
Wouldn't the cm10 be faster then because the phones read and write speed is faster than the ext sd? (Based on what class you have on the sd)?

Sent from my 3D phone.
[LG Optimus 3D] Smeagol44:
Even if I have my GB rom working? And shouldn`t I need to flash v20p? Im on a P925. Im a little confused about all this. Cm10 (on sd) boots ok but no signal. Jellybam reboots after bootanimation. :( also Im using CWM Touch, could this be the problem?
[LG Optimus 3D] berni987654321:
Maybe but cm10 is always faster then stock and stock would be pretty laggy on ext sd6
[LG Optimus 3D] berni987654321:
Maybe but cm10 is always faster then stock and stock would be pretty laggy on ext sd
[LG Optimus 3D] BadMilo:
Great job Bernie, and so is your rom.

If i need to do a factory reset on the second rom is it possible? and if so how?
[LG Optimus 3D] omgomg:
Bernie, do you think it will ever be possible to do this dual boot mode for the people who are with the ICS bootloader? I mean in the future.

Now we have ICS and ported CM10 for that, by iodak. :good:
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

Yes use mke2.fs -T ext4 /dev/block/mmcblk1p3 and mke2.fs -T ext4 /dev/block/mmcblk1p4

Yes i think so. Maybe im going to work on this
[LG Optimus 3D] fabersantucci:
R: [DualBoot]How-to[GB/JB]

Dual boot ics-cm10 is possibile ???
[LG Optimus 3D] berni987654321:
not yet but soon
[LG Optimus 3D] Smeagol44:
Finnally got this to work flawlessly!! Acura 3D Max as main system and Jellybam as second.

Just a quick question, is there any change we can get a cm10_pac kernel with overclock options? That would be awesome. =)
[LG Optimus 3D] Smeagol44:
This is really odd.

First time I flash the second system (in my case: Jellybam) it works flawlessly... until I reboot.

Then I won't get signal, baseband is not recognized, IMEI is "unknown", and after 2 minutes or so, the system reboots.

Strange thing is, Acura's Rom (my first-boot system) shows i'm on v21e baseband, and Jellybam (in the first boot after flashing) shows i'm on v20p.

WTF is going on here?

Should I re-flash the v21e baseband? What do you guys recommend me to do? Is there some way I can know what baseband I'm on for sure?

I know I been making a lot of questions and been kinda annoying here, I'm sorry for bothering you guys.

Again, thanks in advance!

EDIT: Ok, forget about this. I finally got it to fully work after flashing Berni's files (x-boot, u-boot, etc) and a stock v21e baseband. Now I have stock v21e and Jellybam. Thanks everyone !!
[LG Optimus 3D] seven1367:
THANKS.

How do I switch between JB and GB? and, how do i back the stock?
[LG Optimus 3D] defcomg:
Re: [DualBoot]How-to[GB/JB]

With wkparks boot loader maybe wkpark could add ROM slots to the boot menu where you see normal recovery fastboot
[LG Optimus 3D] berni987654321:
we could check his uboot source on github there should be the boot menu
[LG Optimus 3D] brajesh.sharma87:
I have installed wkpark bootloader v1.25a and currently on cm10. Is it possible to dual boot promethius rom and cm10 together using this bootloader?

P.S.: I have never flashed stock ICS. (If that matters)
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

Most likely not
[LG Optimus 3D] brajesh.sharma87:
Any particular reason? I am saying coz single booting premethius or cm10 does work with this bootloader.

I know you are too busy but request you to organise your dual booting guide a bit so that more people can be benifited with it. This is one of the most wonderful thing and most of the optimus 3d users require it. The only way to use full featured 3d is to use a stock GB rom but at the same time people are not satisfied with GB as os on their phone and want to try cm10. Your dual boot is the only cure for such people.

I appreciate the effort that you've put for the community here.
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

OK I didn't knew that booting promethius ROM would be possible on ICS boot loader (or wkparks) then it could be possible but I don't see any reason to boot GB ROMs on ICS partition table
[LG Optimus 3D] Smeagol44:
@Bernie, could this method work for other devices? (like the Galaxy SII ?) I'm sure the SD card could be formated, and the ROM modified (updater-script) in the same way. But what about the kernel? Is it easy to modify a kernel to make it boot an ext-sd rom?

Thanks in advance!!
[LG Optimus 3D] brajesh.sharma87:
easy or hard I dont know but its possible for sure. see this - http://xdaforums.com/showthread.php?t=1169953&highlight=dual+boot

and for devices like galaxy s2, there are kernel devs who kernels supports native dual boot. For other second init devices, they do it via bootmenu.
[LG Optimus 3D] Smeagol44:
Yeah I know. But that's like a "Virtual" dual boot. Bernie's method is a true dual boot. Just wanted to know if some of you does know how to modify a kernel to work like Bernie's. Also it would be good so that we can modify other P920's kernels as for overclock ourselves, so we don't have to rely or wait for other people/developers.

Just saying, if we can learn how to modify kernels for this, ANY device could have dual boot. Or am I wrong?
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

I already posted that i m going to put my work in github dual boot is pretty easy after figguring out what to modify but i m having some problems with github so there will be most likely a how to. Maybe it will be in Android chef central cause this way should work on all Android devices whith unlocked bootloader
[LG Optimus 3D] Smeagol44:
You're a dual-boot god, Bernie.

I'll be waiting for those 'how-to'. =)
[LG Optimus 3D] OptimusRs:
Hey berni i try to make dual boot but wen i put my device in recovery and connect the cable i open cmd and write adb shell

it show me device is not found :confused:
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

You have to install the correct ADB drivers you can search in google for somebody in o2x section he made a modified version of ADB drivers try them if nothing else works
[LG Optimus 3D] BadMilo:
Re: [DualBoot]How-to[GB/JB]

You probably have newest cwm or twrp install cwm from dark lestats thread and it will work, i had the same issue myself
[LG Optimus 3D] :
Is it possible to dualboot CM10 + PACman roms?
[LG Optimus 3D] berni987654321:
yes just use the cm10 or pacman rom instead of gb rom
[LG Optimus 3D] lzzar:
Sv: [DualBoot]How-to[GB/JB]

Now with wkparks 1.25 we can dualboot ics and cm10 or ics and GB.

Sent from my 3D phone.
[LG Optimus 3D] berni987654321:
did yout tested it?
[LG Optimus 3D] lzzar:
Sv: [DualBoot]How-to[GB/JB]

No but i think am going to. Why shouldnt it work? GB, ics and cm10 and cm10.1 can all run on 1.25

Sent from my 3D phone.
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

Report please back
[LG Optimus 3D] lzzar:
Sv: [DualBoot]How-to[GB/JB]

Will do

Sent from my 3D phone.
[LG Optimus 3D] Smeagol44:
Guys, I'm having an issue here. After trying to install CM7 in internal SD (Wich I did, and it worked), everytime I try to call or whenever someone calls me, the call ends at after 10 seconds or maybe less. This happens on every single rom I've tried, even after removing CM7 and deleting the partitions. It happens on Acura Max 3D, CM10 and Jellybam. (Also happened in CM7)

Do you know what can be causing this??

Thanks in advance!
[LG Optimus 3D] dreccon:
Re: [DualBoot]How-to[GB/JB]

@berni

I am wondering, when Android is operating, is the kernel running directly from ROM or does it first load itself into the RamDisk?

If it is running from RamDisk, then we might be able to use the dd command from terminal to hot-flash it and reboot straight into the other ROM. No need to boot into recovery this way!

A possible script could look like this:

We could even put a shortcut to this script in our homescreen to speed things up.

If, on the other hand, the kernel is running straight from ROM, then, I guess, the system will hang before flashing is complete.

What do you think?

@EVERYONE ELSE

I am NOT a dev! I just had an idea. Do NOT try this script before a dev approves it!

Sent from my 3D phone
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

That one works
[LG Optimus 3D] dreccon:
Re: [DualBoot]How-to[GB/JB]

You tried it already?

Sent from my 3D phone
[LG Optimus 3D] berni987654321:
AW: [DualBoot]How-to[GB/JB]

No the whole script but the boot partition get only affected when the phone boots, the it gets splitted into ramdisk and kernel. You can make any change to init.rc or any other file at / directory when you reboot the change wont be there any more. You can flash while booted any image to mmcblk0p5 and nothing will happen until you reboot. So yes it should be possible to use that script(at least the dd stuff, the stuff with echo i didn't tried)
[LG Optimus 3D] dreccon:
Re: [DualBoot]How-to[GB/JB]

The echo stuff is nothing! It's just a precaution in case flashing goes wrong!

I'll upload scripts and instructions soon. This will be my tiny contribution to your gigantic work! Thank you!

Sent from my 3D phone
[LG Optimus 3D] dreccon:
This is a way to easily switch ROMs

I have created a new thread with instructions on how to make ROM switching work with a click of a button (you do all the work once)! This way I hope to attract more people into using one or the other form of CM10 and speed development!

Update: Some people reported difficulty in creating the last partition in the external SD, if the card is larger than 8GB. So, I have added a detailed guide for that too.

Do not forget: It was

Berni

who made this possible in the first place!

Show the guy the respect he deserves!

:good:
[LG Optimus 3D] lzzar:
Re: [DualBoot]How-to[GB/JB]

Now this is the ultimate dualboot! Awesome man!

Sent from my 3D phone.