Dual boot your Samsung Galaxy S3

If you own a Samsung Galaxy S3 and have also used AOSP ROMs, you'd know the awesomeness of both TouchWiz and AOSP ROMs (cyanogenmod, AOKP etc). The vanilla experience of AOSP and the goodies of Samsung's TouchWiz are both very tempting and it's very difficult to choose between the two. For this reason, XDA Elite Developer gokhanmoral has made a new kernel (SiyahKernel) with a custom recovery which enables you to dual boot your i9300 and enjoy both flavors.
Before we start, here are a few things to keep in mind:

• Always make a nandroid backup in case anything goes wrong.
• The kernel only supports TouchWiz and AOSP Jelly Bean ROMs (Any Ice Cream Sandwich or MIUI ROM is NOT supported) [Update: The latest build from MIUIAndroid is supported. Tested and working.]
• Keep a backup kernel and recovery to flash, just in case you're not happy with Siyah.

Let's get started. Firstly, download the latest SiyahKernel from the developer's website. Transfer the ZIP to your phone and flash it through recovery. Reboot into your primary ROM and find the app STweaks. If it hasn't appeared, download it from Play Store for free. In STweaks, go to Dual Boot options and click "Hijack Recovery". Reboot into recovery.

In Siyah recovery, follow these steps:
Dual boot options.

• Format 2nd ROM data, wipe cache, wipe dalvik cache.
• Install 2nd ROM from (location)
• Flash gapps
• Flash SiyahKernel again to 2nd ROM
• Reboot.

Once you've rebooted, you'll find that to reboot into the secondary ROM, you have to press the Home or Volume down key while it's booting. You can also boot into the 2nd ROM from STweaks. Another useful feature of STweaks is the slide2wake option, it is really awesome.
Enjoy!
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