[KERNEL]DualBoot - Devil4.2 (06-Feb-2013)

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DerTeufel1980

Inactive Recognized Developer
Jul 31, 2011
10,368
27,668
Attention! Before installing this kernel, read carefully (don't forget reading post 2!)!

1.) Make a Nandroid!
2.) If you are installing this kernel the first time, it wipes your data and system! (this is caused by creating the secondary system partition) - you can restore your nandroid afterwards
3.) Make sure to have 700 mb free space at your internal sdcard (this is needed for secondary data)
4.) You can't install a rom as secondary rom, without doing some work yourself! This is caused by the way, rom installing is mounting the system partition. I can't do anything against it (What you need to do is written in the guide of post 2)
5.) You only can install 4.2.1 roms, with the "default"/cm partition layout!
6.) You have to install the kernel again, after you have installed a new rom. If you forget to install it, you just boot up to primary rom.


Many thanks to:

- cm team, especially pawitp
- stratosk
- mialwe
- zachariasmaladroid
- kasper_h
- krarvind
- kufikugel
- gokhanmoral (great idea to build a dualboot kernel, always helpful)
- Bejda
- sUsH667 ( i have taken his design for aroma filemanager, it's looking great)
- amarullz ( who coded the filemanager)
- ...
 

DerTeufel1980

Inactive Recognized Developer
Jul 31, 2011
10,368
27,668
About this kernel (and installing it):

installing a dualboot kernel the first time:
1.) the kernel needs to create a secondary system partiton. this is taking place at the current /data partition.
b) the new version (04-Feb.) is creating an addional "devil" partition of 20 mb. it currently isn't used, but i am preparing already for later (boot.img is limited to 7.5 mb in size because of the boot partition size), because the dualboot kernel needs to include more files as the stock one, and for 4.1.2 support, i even need to include more...
2.) by installing the kernel the first time, data and system get deleted due to the partition change.
3.) as a security feature, the install fails the first time, before your data gets formated. if your install fails, you still can make a nandroid, if you didn't before. then just install again. this time the install does not fail. the kernel reboots to recovery automatically now
4.) install the kernel a third time
5.) before installing a new rom, go to advancend, reboot recovery
6.) after installing a rom (primary or secondary), flash the kernel again, follow the steps below for this!

updating the dual boot kernel to a newer version/installing the kernel after a rom flash:
1.) flash the kernel
2.) reboot to recovery (just in case...)


how to revert the partition changes:
there also is a "revert" kernel now, which is available here:
http://rootaxbox.no-ip.org/derteufel/jellybean4.2.x/

if one isn't using the dualboot kernel, the "revert" kernel doesn't revert anything, but is a normal single boot kernel, with the same features as the dualboot one.

if one is flashing reset kernel after dualboot, you need to flash it three times. the first install just fails. the second one succeds and reboots to recovery. the third one finishes the restore.
The reset kernel wipes data and system, (only) if coming from dualboot kernel!

in the recovery:
1.) by default, there is no entry for system and data in the fstab. i have done this, to ensure you don't install apps/packages to the wrong rom. this means, if you just go to install zip, install fails, because there is no system partition which can be mounted.
2.) the dualboot menu. what do these options do?
a) the first two options are mounting primary/secondary filesystem right after clicking.
b) these two options are preparing for mounting primary/secondary filesystem after you reboot to recovery. without using this, you don't have the options in recovery, to mount/format data or system, etc
3.) reboot primary/secondary system should be clear ;)


how to install a rom as primary/secondary rom:
1a ) remove spaces from filename!
1b )install zip from sdcard
2.) choose from where to install
3.) choose what and where to install
note: the kernel installs itself after the rom. no need to reflash. this does not work with elite rom (because of the zip design)

How to create/restore a nandroid:
1.) go to dual boot menu
2.) select "enable mounting of pri. fs" or select "enable mounting of sec. fs"
3.) reboot to recovery
4.) backup or restore your nandroid, depending on your previous choise, you'll backup/restore the primary or secondary system
5.) consider to rename your backup, to something like primary_date or secondary_date


here you get the kernel. nothing else needed:
http://rootaxbox.no-ip.org/derteufel/dualboot/
 
Last edited:

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
Nice work. Sounds like an interesting concept and seems pretty easy, but I'm not so sure I want to dual boot my phone just yet :x

*edit*
For those who want to have the same apps installed for both ROMs would it be feasible to have a linked data?
 
Last edited:

VashTS

Senior Member
Dec 4, 2011
169
14
This seems cool as hell I just maybe dual boot 4.2 and 4.1. Awesome work DT!
 

DerTeufel1980

Inactive Recognized Developer
Jul 31, 2011
10,368
27,668
AW: [KERNEL]DualBoot - Devil4.2 (06-Feb-2013)

Nice work. Sounds like an interesting concept and seems pretty easy, but I'm not so sure I want to dual boot my phone just yet :x

*edit*
For those who want to have the same apps installed for both ROMs would it be feasible to have a linked data?

This isn't possible. You need to install it twice.





This seems cool as hell I just maybe dual boot 4.2 and 4.1. Awesome work DT!

For now, only 4.2.1 is working

Gesendet von meinem GT-I9000 mit Tapatalk 2
 

ThdDude

Senior Member
Sep 27, 2010
2,303
4,823
Kansas City
Running HellyBean and Slim Bean works great!!
Kinda reminds me of how on the HD2 we ran multiple ROMs on EXT partition, but they could share data.
 

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
So I flashed this Kernel yesterday from Semaphore and SlimBean 4.2.1 RC2 and it went smooth until I decided to restore my apps. Nandroid didn't restore correctly (I'm guessing because I made it from Semaphore and should have flashed the "revert" kernel first and made it with that) and TiBu hung while doing a batch restore so now I'm going through and restoring them individually. I'm hoping it'll work out this way.

*edit*
Seems the issue with TiBu is as I expected. Insufficient space due to a smaller data partition as noted in the OP.
 
Last edited:

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
Other then the restoring backups issue (which I managed to take care of) this kernel's working as good as expected (like the previous Devil Kernels but with the dual boot option). Would be nice if there was an app or something that would allow me to reboot to the other partition without having to go into recovery first.
 

They Drew First Blood

Senior Member
Aug 27, 2011
369
240
Devil_DualBoot Cappy

Great to see this for the Cappy, even though I had no issues testing with the i9000 version. @Kyuta, the Nandroid should work once it is created from within this dualboot kernel, and the Nandroids should also work for their respective partitions too (primary or secondary). I like the suggestion in the OP to label Nandroids accordingly. This kernel has given me the ability to have a daily driver on one partition and test things out on the second, which is awesome :) Thanks so much DerTeufel, hope all is well with you.
 
Last edited:

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
Great to see this for the Cappy, even though I had no issues testing with the i9000 version. @Kyuta, the Nandroid should work once it is created from within this dualboot kernel, and the Nandroids should also work for their respective partitions too (primary or secondary). I like the suggestion in the OP to label Nandroids accordingly. This kernel has given me the ability to have a daily driver on one partition and test things out on the second, which is awesome :) Thanks so much DerTeufel, hope all is well with you.

Like I mentioned in my post i had used Semaphore, but had I flashed the single boot kernel first (to keep from having all my data wiped) then made the nandroid it probably would have worked. Flashing the dual boot to make the nandroid would have wiped what I was trying to backup.

On another note ran into a few issues that I'm not sure what the cause of them were so I'm not going to bother mentioning them anymore since I think they were mostly user error and not kernel related, but I think I've managed to work through them now. Love being able to flash and test ROMs without losing my daily driver.
 

They Drew First Blood

Senior Member
Aug 27, 2011
369
240
RE: restoring backups

Like I mentioned in my post i had used Semaphore, but had I flashed the single boot kernel first (to keep from having all my data wiped) then made the nandroid it probably would have worked. Flashing the dual boot to make the nandroid would have wiped what I was trying to backup.

Yes, exactly. Thank you. I didn't try an advanced nandroid restore, but individually restoring apps through TiBu did work fine.
 
Last edited:

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
Yes, exactly. Thank you. I didn't try an advanced nandroid restore, but individually restoring apps through TiBu did work fine.

I first did the full nandroid restore which was a mistake since it gave me back semaphore and I had to reflash Devil Kernel. Did the advanced restore after which only allowed me to select if I wanted boot, system, or data to be restored (might have been a few more, but those are what I remember off the top of my head) which didn't help any.
 

Kyuta Syuko

Senior Member
Aug 18, 2009
1,867
660
Anyone else having issues with apps disappearing from your ROMs? Haven't really installed many apps to the secondary partition but the apps on my primary partition that I have installed on my SD Card keep disappearing. Might have been the data wipe/factory reset I did on the secondary partition before flashing a ROM to it.
 

They Drew First Blood

Senior Member
Aug 27, 2011
369
240
Dualboot data wipe

Anyone else having issues with apps disappearing from your ROMs?... ...Might have been the data wipe/factory reset I did on the secondary partition before flashing a ROM to it.

I believe DerTeufel mentioned that a data wipe/factory reset affects both primary and secondary... one sec...

You need to use the third and fourth option from dualboot menu. Select three, reboot recovery, wipe data (primary in this case). Then select fourth option, reboot recovery and wipe again (secondary)
Gesendet von meinem GT-I9000 mit Tapatalk 2

I think those are the procedures for each individual partition, to avoid affecting both partitions when wiping data. Obviously, though, (does it even need to be said?) don't wipe the primary if you're set with it and only want to be dealing with the secondary. You may already be following those steps, I'm sorry that I don't have anything to add myself since I have been fiddling around with Semaphore kernel this week. A few noteworthy posts on this topic in DerTeufel's i9000 Dualboot thread start here http://xdaforums.com/showthread.php?p=37118166#post37118166
 
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  • 19
    Attention! Before installing this kernel, read carefully (don't forget reading post 2!)!

    1.) Make a Nandroid!
    2.) If you are installing this kernel the first time, it wipes your data and system! (this is caused by creating the secondary system partition) - you can restore your nandroid afterwards
    3.) Make sure to have 700 mb free space at your internal sdcard (this is needed for secondary data)
    4.) You can't install a rom as secondary rom, without doing some work yourself! This is caused by the way, rom installing is mounting the system partition. I can't do anything against it (What you need to do is written in the guide of post 2)
    5.) You only can install 4.2.1 roms, with the "default"/cm partition layout!
    6.) You have to install the kernel again, after you have installed a new rom. If you forget to install it, you just boot up to primary rom.


    Many thanks to:

    - cm team, especially pawitp
    - stratosk
    - mialwe
    - zachariasmaladroid
    - kasper_h
    - krarvind
    - kufikugel
    - gokhanmoral (great idea to build a dualboot kernel, always helpful)
    - Bejda
    - sUsH667 ( i have taken his design for aroma filemanager, it's looking great)
    - amarullz ( who coded the filemanager)
    - ...
    13
    About this kernel (and installing it):

    installing a dualboot kernel the first time:
    1.) the kernel needs to create a secondary system partiton. this is taking place at the current /data partition.
    b) the new version (04-Feb.) is creating an addional "devil" partition of 20 mb. it currently isn't used, but i am preparing already for later (boot.img is limited to 7.5 mb in size because of the boot partition size), because the dualboot kernel needs to include more files as the stock one, and for 4.1.2 support, i even need to include more...
    2.) by installing the kernel the first time, data and system get deleted due to the partition change.
    3.) as a security feature, the install fails the first time, before your data gets formated. if your install fails, you still can make a nandroid, if you didn't before. then just install again. this time the install does not fail. the kernel reboots to recovery automatically now
    4.) install the kernel a third time
    5.) before installing a new rom, go to advancend, reboot recovery
    6.) after installing a rom (primary or secondary), flash the kernel again, follow the steps below for this!

    updating the dual boot kernel to a newer version/installing the kernel after a rom flash:
    1.) flash the kernel
    2.) reboot to recovery (just in case...)


    how to revert the partition changes:
    there also is a "revert" kernel now, which is available here:
    http://rootaxbox.no-ip.org/derteufel/jellybean4.2.x/

    if one isn't using the dualboot kernel, the "revert" kernel doesn't revert anything, but is a normal single boot kernel, with the same features as the dualboot one.

    if one is flashing reset kernel after dualboot, you need to flash it three times. the first install just fails. the second one succeds and reboots to recovery. the third one finishes the restore.
    The reset kernel wipes data and system, (only) if coming from dualboot kernel!

    in the recovery:
    1.) by default, there is no entry for system and data in the fstab. i have done this, to ensure you don't install apps/packages to the wrong rom. this means, if you just go to install zip, install fails, because there is no system partition which can be mounted.
    2.) the dualboot menu. what do these options do?
    a) the first two options are mounting primary/secondary filesystem right after clicking.
    b) these two options are preparing for mounting primary/secondary filesystem after you reboot to recovery. without using this, you don't have the options in recovery, to mount/format data or system, etc
    3.) reboot primary/secondary system should be clear ;)


    how to install a rom as primary/secondary rom:
    1a ) remove spaces from filename!
    1b )install zip from sdcard
    2.) choose from where to install
    3.) choose what and where to install
    note: the kernel installs itself after the rom. no need to reflash. this does not work with elite rom (because of the zip design)

    How to create/restore a nandroid:
    1.) go to dual boot menu
    2.) select "enable mounting of pri. fs" or select "enable mounting of sec. fs"
    3.) reboot to recovery
    4.) backup or restore your nandroid, depending on your previous choise, you'll backup/restore the primary or secondary system
    5.) consider to rename your backup, to something like primary_date or secondary_date


    here you get the kernel. nothing else needed:
    http://rootaxbox.no-ip.org/derteufel/dualboot/
    3
    I am no developer but I don't believe so. I assume it would do something like copy from the current /boot partition somehow. Or maybe just remove the boot.img from the zip file before flashing. Or comment out the applicable kernel installation routine in the updater-script... :confused:

    Oh wow, I totally missed this question...

    My script inside the recovery copies the kernel from your boot partition to the sdcard and then it gets placed inside the new rom.

    Gesendet von meinem GT-N7105 mit Tapatalk 2
    2
    Devil_DualBoot Cappy

    Great to see this for the Cappy, even though I had no issues testing with the i9000 version. @Kyuta, the Nandroid should work once it is created from within this dualboot kernel, and the Nandroids should also work for their respective partitions too (primary or secondary). I like the suggestion in the OP to label Nandroids accordingly. This kernel has given me the ability to have a daily driver on one partition and test things out on the second, which is awesome :) Thanks so much DerTeufel, hope all is well with you.
    2
    RE: SD card apps lost

    And I was saying I had used the fourth option and rebooted into recovery with the second partition mounted when I did the wipe but the apps that I had installed to the Primary Partition and then moved to the SD Card got wiped as well.

    SD card, how did I miss that, for a minute there I thought I had a good answer... looks like I edited out the main point of your post when I quoted it :eek: I wasn't implying that you were going about it wrong, I was mainly posting the info for other viewers that may be running into similar issues, and there are some good points in his other thread once it is sifted through. That is an interesting enough issue that I am going to try to replicate it- there is a new Hellybean to flash anyway.
    EDIT: Confirmed. Various apps disappear from primary ROM when data wipe performed on secondary ROM. Doesn't seem to be an issue when data wipe performed on primary ROM however.