It is well known that a computer can have more than one Operating System. Similarly, some Android devices also support 2 Operating Systems simultaneously and Samsung Galaxy S2 I9100 is one of those rare devices. This feature is known as Dual Boot. This is achieved by sharing the kernel and using a hidden partition in dev/block to store the 2nd ROM’s /system and the /sdcard (Internal storage) to store /data and /cache inside a hidden folder (/sdcard/.secondrom).
This feature can solve the doubt of a user – whether to use the stock Touchwiz ROM or switch to a CyanogenMod based ROM. An individual can have both the ROMs at the same time. It should be noted that Gingerbread ROMs are not supported. The user must be on Ice Cream Sandwich or above.
Follow the instructions given below.
- Samsung Galaxy S2 I9100 must be rooted
- ClockworkMod Recovery installed
- Siyah Kernel zip file
- CM 10.1 zip file
- Gapps zip file
- Download the Siyah Kernel zip file and CM 10.1 zip file and place it on the SD card.
- Boot in to the recovery mode.
- Now go to “Select zip from SD card” and choose the Siyah Kernel zip file.
- Go back and select reboot to CWM recovery.
- Navigate to “Dual Boot options”.
- Select the option “Wipe 2nd ROM data/cache”. This will prepare your phone to flash the 2nd ROM.
- After having that done, select the option to wipe the dalvik cache.
- After all that is done, select either “Install 2nd ROM from Internal SD card” or “Install 2nd ROM from External SD card” depending on the location of your ROM.
- Now choose the CM 10.1 zip file.
- After the process is over, reboot.
- Press the Home button or volume down to enter the Secondary ROM.
- Flash the Gapps in a similar way.
Instead of using the CM 10.1 ROM, the user can select any ICS/JB ROM of his/her choice.