How to Run Android N as Secondary ROM on Android along with Primary ROM

I was looking for some trick to run Android N along with current Android Marshmallow on my Nexus 6. I didn’t want to flash the factory image and lose all the data from my phone. After trying for couple of times I figured out a way to run Android N as secondary ROM on Android.

Before we move forward, know that It is an experimental method and it can be risky so try at your own risk. After this guide you would be able to try out Android N on your phone, your phone will still have primary ROM, which can also be used.

Lets move on to our guide, perform at your own risk. Make a backup of your phone and its data before you proceed further.

Run Android N as Secondary ROM on Android along with Primary ROM:

First of all, consider these prerequisites that you should have on your phone before you move forward.

• Rooted Device with TWRP.
• ADB/Fastboot Installed along with the drivers.

Move on to the next steps if you are done with pre-requisites.

Following are the download you would require in order to perform this whole process of installing Android N as secondary ROM on Android phone.

• Download Factory image of Android N developer Preview.
• Direct link to the Flashable zip file.

1. First of all, in order to use the MultiROM with zip file. You have to delete all the bootloader related files and radio from the zip. The final version of zip should only contain boot.img and system related files. (This is needed to be done because otherwise each time you reboot, the bootloader is flashed that is quite risky).
2. Now on your Android device, Install MultiROM Manager from the play Store. let it install on your phone.
3. Now copy the modified zip file from first step to your device.
4. Make TWRP backup of your existing system and backup the contents of your SD card.
5. Reboot the bootloader and Flash the bootloader and radio from factory preview image  (First download mentioned above).
6. Now Boot into recovery and select the MultiROM option. From there select the option “Add New ROM”.
7. Select the Zip file and then select the modified zip file from SDcard.
8. Let it do its job. After it is done, Reboot and Select the Secondary ROM at Boot.
9. First boot into Android N, It might take some time and then it will start working properly.

That’s it.. Now you can run Android N as secondary ROM on Android along with Primary ROM.

Note: If you ever wish to remove the developer preview of Android N from your phone, boot into primary ROM, and then from MultiROM manager, remove the Android N.

Also Know that while performing above guide I’ve assumed your primary ROM is encrypted. In care your ROM is decrypted, you can replace the boot.img in the Android N preview zip file with the encrypted boot.img of your choice and flash.

DO NOT mix the decrypted ROM with encrypted (default) N as it will wipe and encrypt your SDcard.

That it. I hope you guys found this guide on how to Run Android N as Secondary ROM on Android along with Primary ROM useful, If you have any queries or issues regarding this guide, let me know in the comments.

EDIT: If you already have MultiROM installed on your Android phone. Boot into recovery, chose to add a secondary ROM and select the Flashable ZIP of Android N preview. Once its finished. You will have two separate ROM. I performed on my Nexus 6, After doing this process. I had my orignal based 6.0.1 and N preview ROM.