Dual-Boot FAQ thread | devil2-kernel by DerTeufel1980 [Note 2]

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n4553

Member
May 29, 2013
5
6
Yes, for now I haven't installed the second rom, however this is what I want to achieve, dual-boot. But firstly I wanted to make sure the kernel is working. I am using Devil recovery, when I flash other things with it, there are no problems...

I got it working! Also dual-boot!

Initially I played only with Devil kernel and kernels from nandroids of Cyanogenmod / stock. And for all I used and I'm using Devil recovery. Every time when I flashed DB kernel, the strange behaviour was present (4-5 minutes at boot, no touchscreen, reboot at waking from sleep). And I tried this several times (also restoring nandroids, flashing again kernel... ).

At RichMD recommendation I tried Perseus kernel. This worked from the first time.
After that I flashed again DB kernel and now the previous problem was no longer present! Maybe the Perseus kernel made a change to my system? I don't know.
Thank you very much!
 

n4553

Member
May 29, 2013
5
6
Switch between ROMs

I wanted to automate a bit the switching between the 2 ROMs, without going through recovery, so this is what I've done:

- Install "GScript Lite" , free from Google Play, on primary ROM.

- On first ROM, open this app, press Menu button -> Add script
Script name, eg.: Reboot second ROM
Check the "Need SU"
In the script text, write:
Code:
echo 1 > /data/.secondaryboot
reboot
- Save script

- You can add a shortcut to the script to homescreen, by going to All apps -> Widgets, drag "GScript Lite" and then select the name of your script
- Tap the script shortcut, to make sure it's working. Grant the root access, and the phone should quickly reboot in the second ROM

- On the second ROM, install this app, create a new script named eg.: Reboot first ROM
- On the text script, write:
Code:
echo 0 > /.secondrom/.secondaryboot
reboot
- Also make sure "Need SU" is checked, save and make a shortcut if you want, and test it.

Hope this helps, until a key combination is added to the kernel.
I would post this to DerTeufel's thread, but I'm a "noob", I don't have rights to post on dev threads.
 

JoyMoro

Senior Member
May 2, 2011
87
21
Mumbai
I am getting error at step 6.


How did u get it working since i got the same issue here?

You need to mount Secondary System in due boot menu

duel boot menu -enable mounting of sec File.


regards
Joy

---------- Post added at 01:14 PM ---------- Previous post was at 12:49 PM ----------

I wanted to automate a bit the switching between the 2 ROMs, without going through recovery, so this is what I've done:

- Install "GScript Lite" , free from Google Play, on primary ROM.

- On first ROM, open this app, press Menu button -> Add script
Script name, eg.: Reboot second ROM
Check the "Need SU"
In the script text, write:
Code:
echo 1 > /data/.secondaryboot
reboot
- Save script

- You can add a shortcut to the script to homescreen, by going to All apps -> Widgets, drag "GScript Lite" and then select the name of your script
- Tap the script shortcut, to make sure it's working. Grant the root access, and the phone should quickly reboot in the second ROM

- .



Hi
Tried this on Primary Rom, Its not working. Checking again.n will also test for secondary Rom n let yoiu know

JoyMoro
 

JoyMoro

Senior Member
May 2, 2011
87
21
Mumbai
You need to mount Secondary System in due boot menu

duel boot menu -enable mounting of sec File.


regards
Joy

---------- Post added at 01:14 PM ---------- Previous post was at 12:49 PM ----------





Hi
Tried this on Primary Rom, Its not working. Checking again.n will also test for secondary Rom n let yoiu know

JoyMoro

it is working alright on both rom
thanks
 

MajorTom_

Senior Member
Feb 17, 2011
966
285
No word yet on how to remove dual boot?

Sent from my SGH-T889 using xda premium
 

RichMD

Senior Member
Jan 8, 2011
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No word yet on how to remove dual boot?

Sent from my SGH-T889 using xda premium
I will post in the FAQ later today but basically just flash a different recovery such as TWRP or standard CWM and full wipe (format /system and /data) and that should cove it. Obviously, you would need to reinstall or restore a nandroid - I assume only a backup of the primary would work. I will have to check for the special folders on the SD card and list them in the FAQ.
 
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bdd786

Member
Mar 18, 2009
27
1
App2SD script not working

I have successfully made dual boot working on my Tmobile. ROM1 (Primary): Xenon HD and ROM2 (secondary) Jedi Master 13. I have tried to acitvate App2SD script. Not working in either of the ROMs.Please reply.
 

RichMD

Senior Member
Jan 8, 2011
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I have successfully made dual boot working on my Tmobile. ROM1 (Primary): Xenon HD and ROM2 (secondary) Jedi Master 13. I have tried to acitvate App2SD script. Not working in either of the ROMs.Please reply.

Sorry, but I have no idea if App2SD would be compatible. DerTeufel1980 would have to answer that.
 

paulove

Senior Member
Oct 7, 2008
518
109
Lier
I will post in the FAQ later today but basically just flash a different recovery such as TWRP or standard CWM and full wipe (format /system and /data) and that should cove it. Obviously, you would need to reinstall or restore a nandroid - I assume only a backup of the primary would work. I will have to check for the special folders on the SD card and list them in the FAQ.

I did a nandroid of a Sammy rom from second FS and restored to primary, that is the rom I am using now.

Just remember to choose right FS and mount all partitions needed.

Sent from my GT-N7100 using Tapatalk 2
 

frenkie9999999

Senior Member
Nov 3, 2009
76
26
Caserta
I would just make a small clarification:

The first time you flash the kernel and recovery,
Going to dual boot options, select File System, primary, and then only now you can create the secondary partition.

the first time I've done the procedure, without selecting a FS, the secondary partition doesn't will create.

:good:
 
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RichMD

Senior Member
Jan 8, 2011
1,581
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just 2 questions...

so which works???
both Sammy or CM/AOSP - Sammy ???

and how to revert ??

In theory, any combination of AOSP and Samsung (Sammy) based.
There does seem to be some ROMs that don't work as well with the dual-boot kernel but I don't have a good list yet.
I have been trying to find time to update this thread with the FAQs such as how to revert. Possibly tonight. ..

Sent from my SGH-I317 using Tapatalk 2
 
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Dingchow

Senior Member
Oct 5, 2011
113
83
I will try to update this thread to clarify the methods you can use to enable dual-boot functionality along with common problems and solutions. This is an initial draft that I will update after it is verified (by DerTeufel and others). Additionally, I will try to re-word as necessary to avoid confusion. Hopefully, the list of questions should help you to complete what you are trying to do.

1) Have you flashed the dual-boot (aka DB) kernel yet? If yes, go to step 3

2) Flash the DB kernel: Go to the DB OP here and flash the version for your model type - http://xdaforums.com/showpost.php?p=40410021&postcount=1 N7100 is for non-LTE models and t0lte is LTE enabled (AT&T, Verizon, etc). The zip will NOT list recovery in the name...

3) Have you flashed the DB recovery? If yes, go to step 5

4) Flash the DB Recovery: Navigate to DB OP listed above and flash the version for your model type (as in step 2 above)

5) Have you created the secondary system partition? If yes, go to step 7

6) Create the secondary partition image: Boot into the DB recovery and select Dual Boot Menu > create secondary system image. This will take a couple of minutes. This only has to be done once.

7) Ready to flash primary or secondary ROMs: Note: It is probably a good idea to get in the habit of always selecting the FS (primary or secondary) that you want to affect just to ensure you don't wipe the wrong one, etc. Select Dual boot menu > enable mounting of (pri or sec.)... It stays selected until you boot into recovery and change it. You will see recovery flash (reload) with the appropriate FS selected. Obviously, don't select it again - logic loop... :p

8) You at least need to follow standard ROM installation instructions at this point such as wipe data, etc (as appropriate). Wipe Data/Factory Reset will leave the ROM (typical) and the 2nd option (wipe data-cache-system-preload) will wipe out the ROM completely so you can start "clean". Only the selected FS is modified so the other ROM is not affected. All apps and data are separate for each ROM. SD card storage is common so keep that in mind for an app that exists in both ROMs.

9) Installing to the primary partition does not need any special instructions. You should have already selected "enable primary". Select "Install zip" > Choose zip from sdcard or external > ROM to Primary FS. The difference between the "ROM" and "Zip" selections is that zips do not typically explicitly access the file systems - they use references in recovery.fstab which DerTeufel modified to point to the appropriate locations depending on your selection (primary or secondary). Yes, choosing install zip might work for installing a ROM to primary but NOT to secondary. Also, the intention is to avoid confusion.

10) Installing to the secondary partition MIGHT be more problematic since the zip has to be modified first to replace FS references with the secondary locations. When you select this option, it can take a couple of minutes since it is changing the references and then re-zipping to a modified file on the SD card. Note: The original will be gone (at least if it was originally on the SD rather than the external SD) so make a copy, etc before proceeding if you want it to be available for standard/primary flashing in the future. The modified file will always install to the secondary partition after being modified. Note: Complicated install scripts (such as AROMA) will likely fail. If you want an AROMA based installation then the safest way is to install it to the primary partition, ensure it is working, make a backup and then restore the backup to the secondary partition (using the DB recovery of course). Backup/restore will be detailed below.

11) Recovery does not automatically mount /system, and /data so ensure /cache and these are already mounted before running a zip that will need to modify them

12) Avoiding MTP issues: After flashing a ROM, recovery prompts you to install the DB kernel again. Otherwise, the kernel installed with your ROM will not be able to boot the secondary ROM. However, if you do flash the DB kernel right away (for now at least) you may have a problem with MTP (access from a PC over USB). If you boot the new ROM (with the ROM's kernel which will work for PRIMARY) then MTP should be working. You can then flash the DB kernel after rebooting to recovery and MTP will still work (afaik). Similar to the AROMA note above, you might want to install a ROM to primary first even if you want it in the secondary partition. The install script will not need to be modified and a normal kernel will boot the ROM so MTP will work. Then you can flash the DB kernel, make a backup and restore to the secondary. Hopefully, this is only temporary but at least this workaround exists.

13) Ready to flash zips to primary or secondary ROMs Flashing gapps, etc. simply requires that the correct FS is enabled, /system and /data (as necessary) are mounted and select your target under "Install zip" > "Choose zip from..." > Zip to (primary or secondary).

I will update this tomorrow with more info on backup/restore, common problems, etc. If the format above is not clear, please suggest an alternative.

RichMD
sorry to hijack your thread, delete if you need.. here's what works for me, several times ( I used your and Der Teufel guide as reference) just put it in a step by step guide

After a lot of reading and some tinkering, I've got PACMAN 4.2.2 PA /AOKP /CM10 1on ROM1 and 4.1.2 Mike1986 ARHD17 Sammy on ROM2.

Adb, MTP, Trickster works fine on both.
Working great. Even managed to get Simplistic Framework and Xposed working on rom 2 (Sammy)

simply
(a) first put the rom you want as PRIMARY on your ext sd card, either a flashable zip or a CWM nandroid backup (NOT TWRP).. you will need this later in step 32
1 on your existing rom and kernel combination , flash DT recovery,
2 reboot to recovery
3 go to dual boot options in recovery
4 create second partition
5 reboot to first rom
6 check MTP
7 reboot recovery
8 dual boot menu
9 enable mount primary ( second on list of 3 options )
10 go back, Mounts and storage
11 mount efs, system, data, ext sdcard
12 go Back, wipe data (2nd option for FULL wipe)
13 check mounts again and remount as above
14 flash the rom you want to be as SECOND rom
15 do all your fancy mods now (Xposed etc)
16 check mounts, remount if necessary
17 flash DT dual boot kernel with "flash kernel" option
18 reboot
19 check MTP
20 go to step 7 and repeat 7-11 inclusive
21 do a backup to ext sd

to move the rom to second rom position..
22 dual boot menu
23 enable mount secondary ( third/last on list of 3 options )
24 go back, Mounts and storage
25 mount efs, system, data, ext sdcard
26 go Back, wipe data (2nd option for FULL wipe)
27 go to Backup and Restore
28 restore the rom you made in step 21 from the ext sd
29 reboot to second rom (allow full boot)
30 check MTP, should work
31 do steps 7-13
32 flash, or restore the rom you placed on your ext sd card in the very beginning step (a) ie the one that you want to be as FIRST/PRIMARY rom
33 Reboot

Done

DO NOT FLASH ANY KERNEL AFTER STEP 33 ( the kernel will show in primary rom settings as unavailable but check with Trickster Mod or CPU spy, it will show you that it is DT dual boot kernel)

The above has worked for me several times now, and some steps are overkill..
The 0 folder from 4.2.2 is visible from the Sammy rom but the Sammy files are not visible from 4.2.2 that's why I recommend using the ext sd for the above procedures as a failsafe

Sent from my dual boot GT-N7100 using Tapatalk 2

I wanted to automate a bit the switching between the 2 ROMs, without going through recovery, so this is what I've done:

- Install "GScript Lite" , free from Google Play, on primary ROM.

- On first ROM, open this app, press Menu button -> Add script
Script name, eg.: Reboot second ROM
Check the "Need SU"
In the script text, write:
Code:
echo 1 > /data/.secondaryboot
reboot
- Save script

- You can add a shortcut to the script to homescreen, by going to All apps -> Widgets, drag "GScript Lite" and then select the name of your script
- Tap the script shortcut, to make sure it's working. Grant the root access, and the phone should quickly reboot in the second ROM

- On the second ROM, install this app, create a new script named eg.: Reboot first ROM
- On the text script, write:
Code:
echo 0 > /.secondrom/.secondaryboot
reboot
- Also make sure "Need SU" is checked, save and make a shortcut if you want, and test it.

Hope this helps, until a key combination is added to the kernel.
I would post this to DerTeufel's thread, but I'm a "noob", I don't have rights to post on dev threads.

GENIUS

All work like a charm. I have PACman Rom on primary and Jedi XP on secondary. Everything working.
The one problem was PACman Rom would not boot on Secondary. Was trying to have Jedi XP as primary to start but had to moved to secondary.
 
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AsfaltSame

Senior Member
Oct 3, 2006
198
20
I got it working! Also dual-boot!

Initially I played only with Devil kernel and kernels from nandroids of Cyanogenmod / stock. And for all I used and I'm using Devil recovery. Every time when I flashed DB kernel, the strange behaviour was present (4-5 minutes at boot, no touchscreen, reboot at waking from sleep). And I tried this several times (also restoring nandroids, flashing again kernel... ).

At RichMD recommendation I tried Perseus kernel. This worked from the first time.
After that I flashed again DB kernel and now the previous problem was no longer present! Maybe the Perseus kernel made a change to my system? I don't know.
Thank you very much!


I have the same problem, and I'm running CM 10.1. Isn't Persius a TW kernel? Did you revert back to stock before flashing Persius?

Sent from my GT-N7105 using xda app-developers app
 
Last edited:

n4553

Member
May 29, 2013
5
6
I have the same problem, and I'm running CM 10.1. Isn't Persius a TW kernel? Did you revert back to stock before flashing Persius?

Sent from my GT-N7105 using xda app-developers app

For all my playing with dual-boot I had 2 nandroids of Stock Samsung 4.1.1 rooted and CM10.1 stored on external SDcard. As recovery, only Dual-Boot Recovery and never changed it.
Initially, the Devil kernel always gave me this strange behaviour, and I tried maybe all possibilities.

Then I flashed Perseus kernel having as the ROM the Samsung nandroid. It worked from first time, after that I reflashed Devil kernel and it also worked now! After, I restored CM10.1 on primary and Samsung on secondary and it's working this way (only MTP on Samsung Rom isn't, but I haven't bothered any more).

Perseus-alpha36.3-i9300-CWM.zip from http://xdaforums.com/showthread.php?t=1691401, first post.
 

tkasob

Member
Apr 20, 2011
41
10
At first, I would like thank you for great guide and sorry for my bad English. I hope, that you understand me. I've done everything according to the instruction (I hope :). At the beginng I had small problems with the second partition ROM (bootloop). Now I have on the primary partition Sammy Rom (Moon Rom v. 6.5). There is no problem with MTP. On the secondary partition I tried succesfully install three different 4.2.2 roms (PAC MAN, Asylum CM 10.1 and currently Helly Bean ROM). And there is the same problem. Play Store app doesn't work (crash), also there is a message, "no external memory" (for exaple, when I open Camera app, Gallery app). File manager shows error message: "Doesn't found any file or folder."
What i've done wrong?
Tom

Wysyłane z mojego Transformer TF101 za pomocą Tapatalk 2
 

RichMD

Senior Member
Jan 8, 2011
1,581
764
CT
At first, I would like thank you for great guide and sorry for my bad English. I hope, that you understand me. I've done everything according to the instruction (I hope :). At the beginng I had small problems with the second partition ROM (bootloop). Now I have on the primary partition Sammy Rom (Moon Rom v. 6.5). There is no problem with MTP. On the secondary partition I tried succesfully install three different 4.2.2 roms (PAC MAN, Asylum CM 10.1 and currently Helly Bean ROM). And there is the same problem. Play Store app doesn't work (crash), also there is a message, "no external memory" (for exaple, when I open Camera app, Gallery app). File manager shows error message: "Doesn't found any file or folder."
What i've done wrong?
Tom

Wysyłane z mojego Transformer TF101 za pomocą Tapatalk 2

I just updated the OP with the answer to this very frequently asked question: http://xdaforums.com/showpost.php?p=41953794&postcount=1
I have not included detailed instructions on backup/restore from primary to secondary so post if you have problems.
 

angieri918

Senior Member
Apr 22, 2013
432
72
tulsa
Ok guys so i want this bad!! it looks like theres a lot to setup tho and it feels like it may be a little too far over my head to do on my own.. I havent been able to find any youtube videos on how to install on ATT GNote 2. Can someone help me out with this?? Ill donate to whoever helps me get this on my phone!!!!!:eek:
 

RichMD

Senior Member
Jan 8, 2011
1,581
764
CT
Ok guys so i want this bad!! it looks like theres a lot to setup tho and it feels like it may be a little too far over my head to do on my own.. I havent been able to find any youtube videos on how to install on ATT GNote 2. Can someone help me out with this?? Ill donate to whoever helps me get this on my phone!!!!!:eek:

You can send me questions or messages via PM. You can donate to DerTeufel

Sent from my SGH-I317 using Tapatalk 2
 
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    This thread should clarify the methods you can use to enable dual-boot functionality along with common problems and solutions. Hopefully, the list of questions should help. The initial author of this important thread was RichMD. He has kindly asked me to maintain it further instead of him, as he is too busy for that in the moment. I have accepted it and I do it as of February, 2014. Although I'm an active user of dual boot since I own my N7100, I don't consider myself to be a guru for this and I will highly appreciate any cooperative posts and I will try to add the important information and frequently update this OP.

    IMPORTANT: particulary new users, please read especially careful here and mind, as the features of Devil Dual Boot Recovery have been strongly changed between the updates! I have kept first two parts of this OP the way RichMD has written them. So all the information are regarding pre-F2FS recovery versions (until v6.0.4.4). My screenshots also show only UI of the 6.0.4.4 version. From part 3 onwards, th einformation are regarding entirely newer recovery and kernel versions with F2FS support.

    LIST OF CONTENTS:
    About Devil dual boot recovery
    Part 1: FAQs: dual-boot general
    Part 2: GUIDE: setup dual-boot
    Part 3: FAQs: benefits of F2FS
    Part 4: GUIDE: migrate from ext4 to F2FS
    Part 5: bootloader info & download links

    About Devil Dual Boot Recovery
    • A luxory version of CWM based recovery with touch UI
    • Each choice must be clicked twice by touch navigation (to avoid accidental touch)
    • Navigation can be done by swiping with finger up or down beyond the menu contents
    • The navigation bar on the bottom works identic like with PhilZ recovery
    SCREENSHOTS: (v6.0.4.4, the last pre-F2FS version)
    attachment.php



    attachment.php



    attachment.php

    1: FAQs / dual-boot general

    Q.) Can I run all 4.3 and 4.4 AOSP and Touchwiz based ROMs with devil2 dual-boot kernel?
    A.) All AOSP ROMs between 4.3 and 4.4.2 will work, but ATM only 4.3 TW based ROMs will boot, 4.4 isn't yet supported.

    Q.) Why do I keep getting "Something went wrong..." when trying to install a ROM.
    A.) Some people have had this problem when trying to install from the external SD card and the error does not happen after the zip is moved to the SD card. There are additional reasons for that error that I listed below.

    Q.) I am having ... problem with the secondary ROM (Play Store FC, no SD card access, no MTP, it fails to install and affects the primary ROM, etc)
    A.) 4.2 ROMs do not typically install properly to the secondary partition currently. Additionally, 4.1 roms have a problem with MTP frequently or AROMA roms will fail the ROM to secondary install-script-modification step . Instead, install your desired ROM to primary, boot with the kernel included in the ROM and ensure everything works including MTP. Then flash the dual-boot kernel. Then back it up and wipe the secondary partition. Then restore your backup to the secondary.
    Note: DerTeufel has fixed the problem of internal SD card access for 4.2 ROMs for N-7105 (LTE) based phones but N-7100 phones still have the problem. It is being worked on.
    Workaround if you can't access the phone via USB
    You can load and use easy UMS one time. You will have access to the external SD. Simply reboot and then set the app back to the default MTP mode and both should be accessible. You don't need the app after that. - (https://play.google.com/store/apps/details?id=com.mohammadag.samsungusbmassstorageenabler) and you shouldn't need it anymore.

    Q.) Can I revert back to a configuration without dual-boot and how do you do it?
    A.) Yes. Use a file manager with root access on the primary ROM to delete the /data/media/.secondrom folder which contains the 1.5GB file and the data folder. Flash another recovery (CWM or TWRP) and flash as you normally would.

    Q.) I can't seem to get my nandroid to restore to the secondary partition. What am I doing wrong?
    A.) One possible problem is that the secondary /system partition is sized at 1.5GB (recent F2FS kernel version enlarged secondaryFS to 1.9GB). If your nandroid backup has over this amount in /system then it won't work. One possible solution is if you use Titanium Backup (or similar backup program) to do a full backup of apps AND system info. Although it is often written not to restore system info, it is OK if it to the same exact ROM and version. You could then factory reset to wipe it clean, do a nandroid backup and then restore that to secondary. Then install TB and restore selectively only the apps you want. I would probably suggest restoring "missing apps + all system data" but then deselect most of the apps that aren't really necessary. Once that is complete and the configuration is working, you could selectively restore other missing apps and data on a priority basis until you start running low on /system space. TB will show that at the bottom of the initial screen.

    Q.) I tried a fresh install to the secondary partition and it completed successfully but now when I boot the primary ROM, I have what I meant to install to the secondary partition. What's wrong?
    A.) This will happen if you choose "ZIP to secondary rather than ROM to secondary because of what I listed below in initial setup. Choosing ROM to secondary will cause the installation script to be modified to install to the secondary partition or it will error out with "Something went wrong". Zips installation scripts do not need to be modified because they will reference recovery.fstab which has been modified to support the secondary partition (when you select enable secondary FS.

    Q.) Why doesn't vibration work after flashing this kernel?
    A.)
    The default setting for vibration in the kernel is 2%. Use the DevilTools app referenced in DerTeufel's OP and change "Set Vibration Intensity" under the Tweak group.

    Q.) Does exFat work?
    A.)
    The kernel supports it but the recovery has not yet been modified to support it.


    2: GUIDE / how to setup dual-boot

    Initial Setup
    1) Have you flashed the dual-boot (aka DB ) kernel yet? If yes, go to step 3

    2) Flash the DB kernel: Go to the DB OP here and flash the version for your model type - http://xdaforums.com/showpost.php?p=40410021&postcount=1 N7100 is for non-LTE models and t0lte is LTE enabled (AT&T, Verizon, etc). The zip will NOT list recovery in the name...

    3) Have you flashed the DB recovery? If yes, go to step 5

    4) Flash the DB Recovery: Navigate to DB OP listed above and flash the version for your model type (as in step 2 above)

    5) Have you created the secondary system partition? If yes, go to step 7

    6) Create the secondary partition image: Boot into the DB recovery and select Dual Boot Menu > enable mounting secondary and then select create secondary system image (also under Dual Boot Menu". This will take a couple of minutes. This only has to be done once.

    7) Ready to flash primary or secondary ROMs: Note: It is probably a good idea to get in the habit of always selecting the FS (primary or secondary) that you want to affect just to ensure you don't wipe the wrong one, etc. Select Dual boot menu > enable mounting of (pri or sec.)... It stays selected until you boot into recovery and change it. You will see recovery flash (reload) with the appropriate FS selected. Obviously, don't select it again - logic loop... :p

    8 ) You at least need to follow standard ROM installation instructions at this point such as wipe data, etc (as appropriate). Wipe Data/Factory Reset will leave the ROM (typical) and the 2nd option (wipe data-cache-system-preload) will wipe out the ROM completely so you can start "clean". Only the selected FS is modified so the other ROM is not affected. All apps and data are separate for each ROM. SD card storage is common so keep that in mind for an app that exists in both ROMs.

    9) Installing to the primary partition does not need any special instructions. You should have already selected "enable primary". Select "Install zip" > Choose zip from sdcard or external > ROM to Primary FS. The difference between the "ROM" and "Zip" selections is that zips do not typically explicitly access the file systems - they use references in recovery.fstab which DerTeufel modified to point to the appropriate locations depending on your selection (primary or secondary). Yes, choosing install zip might work for installing a ROM to primary but NOT to secondary. Also, the intention is to avoid confusion.

    10) Installing to the secondary partition MIGHT be more problematic since the zip has to be modified first to replace FS references with the secondary locations. When you select this option, it can take a couple of minutes since it is changing the references and then re-zipping to a modified file on the SD card. Note: The original will be gone (at least if it was originally on the SD rather than the external SD) so make a copy, etc before proceeding if you want it to be available for standard/primary flashing in the future. The modified file will always install to the secondary partition after being modified. Note: Complicated install scripts (such as AROMA) will likely fail. If you want an AROMA based installation then the safest way is to install it to the primary partition, ensure it is working, make a backup and then restore the backup to the secondary partition (using the DB recovery of course). Backup/restore will be detailed below.

    11) Recovery does not automatically mount /system, and /data so ensure /cache and these are already mounted before running a zip that will need to modify them

    12) Avoiding MTP issues: After flashing a ROM, recovery prompts you to install the DB kernel again. Otherwise, the kernel installed with your ROM will not be able to boot the secondary ROM. However, if you do flash the DB kernel right away (for now at least) you may have a problem with MTP (access from a PC over USB ). If you boot the new ROM (with the ROM's kernel which will work for PRIMARY) then MTP should be working. You can then flash the DB kernel after rebooting to recovery and MTP will still work (afaik). Similar to the AROMA note above, you might want to install a ROM to primary first even if you want it in the secondary partition. The install script will not need to be modified and a normal kernel will boot the ROM so MTP will work. Then you can flash the DB kernel, make a backup and restore to the secondary. Hopefully, this is only temporary but at least this workaround exists.

    13) Ready to flash zips to primary or secondary ROMs Flashing gapps, etc. simply requires that the correct FS is enabled, /system and /data (as necessary) are mounted and select your target under "Install zip" > "Choose zip from..." > Zip to (primary or secondary).

    Kashortiexda has created another installation process documented in post #13 > http://xdaforums.com/showpost.php?p=41992232&postcount=13




    3: FAQs about F2FS / benefits of F2FS and dual-boot in f2fs


    Q.) What is F2FS?
    A.) "The Flash Friendly File System" created by Kim Jaegeuk (Samsung) and released in February 2013. Read more about F2FS here

    Q.) Recently, DerTeufel1980 has updated his devil2 dual-boot kernel and recovery and merged F2FS support. What is the benefit of F2FS?
    A.) if the internal sdcard is formatted to F2FS, the system is supposed to be up to 2 times faster than on ext4 (default formatting).

    Q.) After update to the newest Devil DB Recovery with F2FS support I had problems by installing ROM to the Secondary FS / my nandroid backup was restored with errors
    A.) The newest recovery has enlarged Secondary FS image to 1.9GB (earlier was 1.5GB). This can be cause for many errors. So be sure to create a nandroid backup of your Secondary ROM before you erase /secondrom partition from data/media and to create it again with the new recovery. This is very important to do after the recovery update.

    Q.) What should I do to be able to use the benefits of F2FS on my device?
    A.) Five steps! First: flash new DB recovery & new DB kernel with F2FS support. Second: create nandroid backup(s) of your ROM(s). Third: move all your data from internal sdcard and save them elswhere, as the formatting to F2FS will erase your entire internal sdcard. Fourth: format in recovery mode all the (internal) sdcard partitions to F2FS one by one. Fifth: restore your ROM(s) and data.

    Q.) Can I revert from F2FS back to ext4?
    A.) Yes. You can use either of Devil DB Recovery versions to revert back to ext4 (in the new version you will can choose between F2FS or ext4) or you can simply flash any other recivery that doesn't support F2FS and format with it all the partitions. It will format all back to ext4 (you will have to repeat the procedure like described in the question right before).

    Q.) After return to ext4 I couldn't format /cache back to ext4
    A.) Formatting back to ext4 seems to not work reliably with the newest Devil Touch recovery for N7100. If it is only /cache, it doesn't matter as everything seems to work normally. You can use any other non-F2FS recovery (like TWRP 2.6.3.x or PhilZ touch 6.12.8 to format cache back to ext4)

    Q.) Can I with F2FS update my ROM(s) normally with any nightly build?
    A.) No, it is not recommended, as the nightlies will ATM reformat some of the partitions back to ext4. Well, yes, in fact you can update, but it is quite complicated way around, therefore, F2FS is more practical for those who want to stick longer time with their ROMs and use benefits of very fast performance of their device on F2FS.

    Q.) I've got error message after migration to F2FS when I tried to restore my nandroid backup
    A.) This happens occasionally mostly there is a "can't mount /data" error message. Don't worry about that, simply reboot recovery, format again all to F2FS and restore your nandroid backup then.

    Q.) After migration to F2FS, I can't reach my Secondary FS partition under "dual boot menu", why?
    A.) If the recovery displays "Only with Devil Kernel available" (altough it is flashed already), simply reboot into the Primary FS and reboot into the recovery right after that. Then you will be able to create again the Secondary FS partition and restore your nandroid backup.

    It has been reported at least by one user that System, Data, EFS, & Storage had to be remounted manually every time for successful boot up by switching from Primary to Secondary FS and vice versa.



    DerTeufel1980's features description just after updating kernel and recovery for t0lte to F2FS (N7100 update was released about one week later):

    What's new:
    kernel:
    • added new f2fs filesystem support (supposed to be up to 2 times faster than ext4)
    • introduce the BFQ-v6r2 I/O sched for 3.3
    • block, bfq: add Early Queue Merge (EQM) to BFQ-v6r2 for 3.3.0
    • enable CGROUP_BFQIO by default
    • backport SLUB from Linux 3.3 (thanks to faux123)
    • afsync: replace fput() with fput_light() accordingly
    • cfg80211: Fix memory leak
    • mm: implement WasActive page flag (for improving cleancache)
    • fix triangle away
    • usb: fix 'adb root'

    recovery:
    • completed the rework of recovery ui (primary and secondary rom need to be selected once in dualboot menu) if you can't access dualboot menu, please boot primary or secondary rom with the new kernel once
    • resized secondary system image to 1.9 gb
    • possibility to flash roms to secondary without modifying the zip (you HAVE TO CHOOSE ROM). if this fails, select use workaround (this is the old method) next time
    • added support to format and mount f2fs formated partitions (/system, /data and /cache)
    • if you format data to f2fs (this gives the maximum performance, you have to select primary rom in dualboot menu, then the option will be in mounts and storage: format /data, /data/media and secondary (please backup before, this wipes your internal sdcard as well)

    You only can format data to f2fs, when you select to manage primary Filesystem, because it formats the entire partition, including your internal sd card (which also includes your second rom partitions). Formatting data gives you a complete clean data partition, and you need to backup/restore data, and sdcard (if you backup the sdcard with custom nandroid to external sdcard, you can restore it afterwards, which also restores the secondary rom).

    The kernel 2.4.5b for t0lte fixes boot on Omnirom, as well as fixes Selinux on Samsung rom. By default Selinux is set to "enforcing" now, for Samsung as well as for AOSP roms.

    If one wants to completely disable selinux, you need to create the file: "/.secondrom/.selinux_disable" (if you are currently booted into secondrom, otherwirse the path would be "/data/.selinux_disable" (both is the same file, and creating it, disables selinux for both roms, once rebooted). selinux stays disabled until the file gets deleted again, and the device rebooted.

    On some Sammy roms FC may occur with enforced selinux with the warning: "smartcard service has stopped". Except the fact that only few may know what this service does, usually nothing bad will happen (this message appears once once after boot up)

    WARNING: After "fixing" booting on Omnirom, DerTeufel1980 has warned that f2fs only seems to be working properly on CM11 based roms. Samsung ROMs are at least working with selinux disabled, but Omni ROM breaks baseband if selinux disabled!!



    4: GUIDE / ext4 to F2FS migration

    New Devil Touch-DB-recovery v6.0.4.5 has some new features:
    • Instead of double amount of options (for primary FS or secondary FS, respectively) now there is "dual boot menu" where we can choos which FS to manage
    • Menu text of the secondary FS is displayed now in red color
    • The size of secondary FS partition is now 1.9GB so even big ROMs can be installed as secondary FS
    SCREENSHOT: (new Devil Touch v6.0.4.5 with f2fs support)
    attachment.php




    As described above under F2FS FAQ, we will migrate to F2FS in five steps:


    Step 1/5: flash Devil Touch v6.0.4.5 recovery & kernel with F2FS support for your device (check the download links on the bottom of this post)
    • flash Devil Recovery with F2FS support for your device (download links are on the bottom of this post)
    • reboot recovery (under "power options" on the bottom of the main menu)
    • for single-boot: flash Devil2-F2FS-kernel.zip to your ROM (2.4.5b for t0lte and Verizon / 2.4.6 for N7100)
    • for dual-boot: if you are already dual-boot user, now flash Devil2-F2FS-kernel.zip to both your ROMs: primary FS and secondary FS

    Step 2/5: create now nandroid backup(s) of both your ROM(s):
    • under "Backup and Restore" choose "Custom Backup and Restore"
    • in this sub-menu, choose "Custom Backup to /sdcard1" or optionally: "Custom Backup Job"
    • check for backup only: /system and /data and then >>Start Custom Backup Job<<
    • as the final step choose "Backup to /storage/sdcard1" option (your external micro SD card)
    • repeat the same procedure for your second ROM
    OPTIONALLY: under this step you can also create a full nandroid backups, but just make sure that you then after migration to F2FS restore only /system and /data in "Custom Restore Job"!

    Step 3/5: move all your data from internal sdcard and save them elsewhere, as the formatting to F2FS will erase your entire internal SDcard!
    • use either external SD card, or your PC as storage, as the entire internal phone memory will be erased in the following step.
    • mind that this step can take some time, regarding size of the data that has to be copied (20-30 min)

    Step 4/5: reboot into the recovery to fs=1 (primary) and format under "Mounts and Storage" following partitions to F2FS:
    • format /system
    • format /data, /sdcard and secondrom (this step will destroy the /.secondrom partition)

    Step 5/5: restore your ROM(s) and data.
    • reboot recovery
    • restore your primary FS
    • flash Devil-DB kernel
    • reboot to system and back to recovery
    • create secondary FS partition
    • restore your nandroid backup to secondary FS (if you have used "Custom Backup Job")
    • flash Devil-DB kernel again
    OPTIONALLY: if you have made full nandroid backups under step 2/5 now at this point don't miss that you should restore only /system and /data with "Custom Restore Job" option!
    Finished! Enjoy F2FS :)




    reverting from F2FS back to ext4
    Repeat whole the procedure, just choose under formatting always "ext4" instead of "F2FS"



    5: download links / troubleshooting

    DOWNLOAD LINKS:

    Latest versions of the kernel and recovery without F2FS support for Note 2:
    Devil2 dual-boot kernel MAIN THREAD



    Note 2 kernel and recoveries with F2FS support:
    n7100 Devil2 kernel: download here
    n7100 recovery: download here

    t0lte Devil2 kernel: download here
    t0lte recovery: download here (this one works also for Verizon)

    The newest Devil3 hybrid kernel for N7100 and t0lte: download here



    BOOTLOADER check

    Regarding the fact that Devil2-recovery boots 4.3 and 4.4 ROMs, owners of the Note 2 should mind, that many recent custom ROMs are designed to work flawless only with the recent JB bootloaders. Custom ROMs don't update your bootloader, so your bootloader was flashed together with your latest stock ROM that you were using. While ICS bootloaders are nearly completely outdated, now also earliest JB bootloaders might cause problems and malfunctions. If so, some users will have to consider to update the bootloader.

    Experienced users know: this is a damn risky task, as if Odin fails so that the old bootloader gets erased and new doesn't get properly flashed, only JTAG will be able to revive your device.
    I have made a little guide and provided download link how to flash a knox-free 4.3 MJ5 bootloader for N7100: CLICK HERE
    This 4.3 bootloader will boot any 4.3 or 4.4 OS, but it still has the charging issue (Sammy's fault) if the device is turned off. All the newer 4.4 bootloaders where the issue is solved are KNOX'ed, so bootloader downgrade won't be possible anymore if you use any of the later bootloader versions.



    CAMERA APP TROUBLESHOOTING:

    All who use AOSP custom ROMs (especially CM based ones) on their Note 2 devices might face the "ERROR: can't connect camera" issue. This problem is not devil2 kernel related. The Camera app is crashy on numerous devices. We can have our Camera working reliably, just mind that it is utterly important to keep the phone in clearly defined position when starting the camera (horizontal/vertical) and to be careful by each change of the axis rotation. Also don't view freshly shot photo in your camera app, but close the Camera and use Gallery for that.

    Should you still face the nasty "can't connect..." error, instead of rebooting the OS use either of those apps, that can successfully restart the camera with one click (my N7100 needed to have both apps installed to make reset working, now either works fine):
    Camera (CMFix) app from Play Store
    Restart Camera.apk from HERE
    Devil-DB-Recovery screenshots (v6.0.4.4):
    8
    RichMD
    sorry to hijack your thread, delete if you need.. here's what works for me, several times ( I used your and Der Teufel guide as reference) just put it in a step by step guide

    After a lot of reading and some tinkering, I've got PACMAN 4.2.2 PA /AOKP /CM10 1on ROM1 and 4.1.2 Mike1986 ARHD17 Sammy on ROM2.

    Adb, MTP, Trickster works fine on both.
    Working great. Even managed to get Simplistic Framework and Xposed working on rom 2 (Sammy)

    simply
    (a) first put the rom you want as PRIMARY on your ext sd card, either a flashable zip or a CWM nandroid backup (NOT TWRP).. you will need this later in step 32
    1 on your existing rom and kernel combination , flash DT recovery,
    2 reboot to recovery
    3 go to dual boot options in recovery
    4 create second partition
    5 reboot to first rom
    6 check MTP
    7 reboot recovery
    8 dual boot menu
    9 enable mount primary ( second on list of 3 options )
    10 go back, Mounts and storage
    11 mount efs, system, data, ext sdcard
    12 go Back, wipe data (2nd option for FULL wipe)
    13 check mounts again and remount as above
    14 flash the rom you want to be as SECOND rom
    15 do all your fancy mods now (Xposed etc)
    16 check mounts, remount if necessary
    17 flash DT dual boot kernel with "flash kernel" option
    18 reboot
    19 check MTP
    20 go to step 7 and repeat 7-11 inclusive
    21 do a backup to ext sd

    to move the rom to second rom position..
    22 dual boot menu
    23 enable mount secondary ( third/last on list of 3 options )
    24 go back, Mounts and storage
    25 mount efs, system, data, ext sdcard
    26 go Back, wipe data (2nd option for FULL wipe)
    27 go to Backup and Restore
    28 restore the rom you made in step 21 from the ext sd
    29 reboot to second rom (allow full boot)
    30 check MTP, should work
    31 do steps 7-13
    32 flash, or restore the rom you placed on your ext sd card in the very beginning step (a) ie the one that you want to be as FIRST/PRIMARY rom
    33 Reboot

    Done

    DO NOT FLASH ANY KERNEL AFTER STEP 33 ( the kernel will show in primary rom settings as unavailable but check with Trickster Mod or CPU spy, it will show you that it is DT dual boot kernel)

    The above has worked for me several times now, and some steps are overkill..
    The 0 folder from 4.2.2 is visible from the Sammy rom but the Sammy files are not visible from 4.2.2 that's why I recommend using the ext sd for the above procedures as a failsafe

    Sent from my dual boot GT-N7100 using Tapatalk 2
    6
    Switch between ROMs

    I wanted to automate a bit the switching between the 2 ROMs, without going through recovery, so this is what I've done:

    - Install "GScript Lite" , free from Google Play, on primary ROM.

    - On first ROM, open this app, press Menu button -> Add script
    Script name, eg.: Reboot second ROM
    Check the "Need SU"
    In the script text, write:
    Code:
    echo 1 > /data/.secondaryboot
    reboot
    - Save script

    - You can add a shortcut to the script to homescreen, by going to All apps -> Widgets, drag "GScript Lite" and then select the name of your script
    - Tap the script shortcut, to make sure it's working. Grant the root access, and the phone should quickly reboot in the second ROM

    - On the second ROM, install this app, create a new script named eg.: Reboot first ROM
    - On the text script, write:
    Code:
    echo 0 > /.secondrom/.secondaryboot
    reboot
    - Also make sure "Need SU" is checked, save and make a shortcut if you want, and test it.

    Hope this helps, until a key combination is added to the kernel.
    I would post this to DerTeufel's thread, but I'm a "noob", I don't have rights to post on dev threads.
    4
    Thanks RichMD, appreciated "how-to" guide.

    However a few remarks:


    It means that in the future we won't need to backup then restore Roms which have to be installed with a Aroma Installer?

    In your guide I suggest to add the following b4 Step 5:
    Make a Nandroid backup to save our current configuration! If you don't manage to install DB or if we aren't convinced by DB benefitis we can come back to an "one ROM boot".

    Thanks. I plan to add a "How do you completely remove dual-boot" even if you didn't make a nandroid first but I will add a comment similar to what you mentioned.
    4
    RichMD
    sorry to hijack your thread, delete if you need.. here's what works for me, several times ( I used your and Der Teufel guide as reference) just put it in a step by step guide

    After a lot of reading and some tinkering, I've got PACMAN 4.2.2 PA /AOKP /CM10 1on ROM1 and 4.1.2 Mike1986 ARHD17 Sammy on ROM2.

    Adb, MTP, Trickster works fine on both.
    Working great. Even managed to get Simplistic Framework and Xposed working on rom 2 (Sammy)

    simply
    (a) first put the rom you want as PRIMARY on your ext sd card, either a flashable zip or a CWM nandroid backup (NOT TWRP).. you will need this later in step 32
    1 on your existing rom and kernel combination , flash DT recovery,
    2 reboot to recovery
    3 go to dual boot options in recovery
    4 create second partition
    5 reboot to first rom
    6 check MTP
    7 reboot recovery
    8 dual boot menu
    9 enable mount primary ( second on list of 3 options )
    10 go back, Mounts and storage
    11 mount efs, system, data, ext sdcard
    12 go Back, wipe data (2nd option for FULL wipe)
    13 check mounts again and remount as above
    14 flash the rom you want to be as SECOND rom
    15 do all your fancy mods now (Xposed etc)
    16 check mounts, remount if necessary
    17 flash DT dual boot kernel with "flash kernel" option
    18 reboot
    19 check MTP
    20 go to step 7 and repeat 7-11 inclusive
    21 do a backup to ext sd

    to move the rom to second rom position..
    22 dual boot menu
    23 enable mount secondary ( third/last on list of 3 options )
    24 go back, Mounts and storage
    25 mount efs, system, data, ext sdcard
    26 go Back, wipe data (2nd option for FULL wipe)
    27 go to Backup and Restore
    28 restore the rom you made in step 21 from the ext sd
    29 reboot to second rom (allow full boot)
    30 check MTP, should work
    31 do steps 7-13
    32 flash, or restore the rom you placed on your ext sd card in the very beginning step (a) ie the one that you want to be as FIRST/PRIMARY rom
    33 Reboot

    Done

    DO NOT FLASH ANY KERNEL AFTER STEP 33 ( the kernel will show in primary rom settings as unavailable but check with Trickster Mod or CPU spy, it will show you that it is DT dual boot kernel)

    The above has worked for me several times now, and some steps are overkill..
    The 0 folder from 4.2.2 is visible from the Sammy rom but the Sammy files are not visible from 4.2.2 that's why I recommend using the ext sd for the above procedures as a failsafe

    Sent from my dual boot GT-N7100 using Tapatalk 2
    Thanks, I certainly don't see that as a "hijack". The intent of the thread is to help anyone that is having a problem with the installations. Having multiple methods to try just helps ensure success if they keep trying.