How to dual boot two roms on galaxy s2?


So guys a great tutorial….how to dual boot two roms on galaxy s2…well it works with almost every android phone(2.3 or above). No i am not using LOLbootdualboot app but instead the siyah kernel. So the new siyah kernel has an option to dual boot two different roms. Its pretty much safe and works with most of the ics roms.

Special thanks to Gokhan Moral for the siyah kernel.

You can check him out here.



So the major questions, every mod has its disadvantages…so what are the disadvantages of this?, well here they are:

  1. You cannot FLASH ANY ZIP on the secondary rom.
  2. You cannot wipe data, dalvik cache etc on the secondary rom.
  3. Only dual boot supported yet.
  4. Cannot have a gingerbread and ics rom combination.


So the advantages are as follows:

  1. Works on ICS roms!!!! (works only on ics roms)
  2. Equal boot time for both the roms.
  3. Supports almost all roms as long as the rom supports siyah kernel (so gb roms not supported)
  4. Option to dual boot just like on a pc on startup.(well not exactly the same)
  5. Does not occupy your volume button and prevent from booting into recovery via combo like the other apps…just occupies your home button but still you will be able to boot into recovery/download with the specified combo.

How the hell to do it?

So HOW THE HELL TO DO IT? I know some of you a**holes around here would just leave the post and download and flash siyah kernel, trying to dual boot on their own and messing up their phones…So please follow every step carefully  for god sake. Firstly there are two choices….

1:If you have data data on your phone that you don’t want to lose make a nandroid backup via cwm and flash the rom you want to keep as secondary  and the siyah kernel as well.

2: If you don’t have important data on your phone, just flash the rom you want to keep as secondary and the siyah kernel as well.

And most importantly, after you flash the second rom, wipe dalvik-cache and other things if  the rom requires it to boot otherwise you will have to do all the steps again. Some roms require dalvik cache or cache wipe..and if you don’t do that, they would probably get into a bootloop. So wipe the things you want and PLEASE boot into the rom for atleast once completely because you will not be able to wipe anything after the rom has become secondary!!!

Setting up Dual Boot:

So now comes the part where you have to set the dual boot. So please check that you have flashed siyah kernel. Now boot into recovery, it will be nexus like touch recovery with an option “dual-boot options”. Well select it.
Now just select the view current status option just in case to check if there is any rom.
If yes then select “Remove Secondary ROM”.
Now as you are running the rom you want as secondary, select the “clone primary rom to secondary option”. It should take about 4-5 minutes.
Now reboot completely first and then boot again into recovery, then go to dual-boot options–>view current status, it should mention that a second rom is found depending upon the name of your rom.
This means that you have successfully created the secondary rom. Now flash or restore your primary rom, flash siyah if needed and reboot. Now immediately after the samsung logo(if not changed), you will see a new screen asking you to press the home button if you want to boot into the secondary rom. Do nothing and after 3 seconds it would boot into the primary one.

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