How to install MultiROM on your OnePlus One and boot multiple custom ROMs. If you want to dual-boot or multi boot custom ROMs on your Android device, the first option that comes up is MultiROM. MultiROM is the software which has been able to boot multiple ROMs on many Android phones.
You can boot any Android custom ROM designed for the OnePlus One like CyanogenMod and even Ubuntu Touch. You can boot not only from the internal memory of the phone but also from a USB drive connected to the phone via OTG cable. All in all, MultiROM is the best and safest way to boot different ROMs on your OnePlus One and not only.
There are three things you need in order to install properly MultiROM: MultiROM, modified recovery and a patched kernel. Follow the guide below to learn how to install each of them.
How to install MultiROM
2. Boot your phone into Recovery and flash the downloaded zip file.
How to install modified recovery
1. Download the modified recovery file here.
2. There are two ways of installing it. Fastboot or through Flashify app which you can download here.
How to install patched kernel
1. Download the patched kernel for AOSP ROMs here. Other supported kernels are Franco and Furnace.
2. Boot your phone again in Recovery and flash the downloaded zip file.
Now you have successfully installed MultiROM. The most difficult part of the process is over. Now you simply have to download and install all the custom ROMs you want.
How to add ROMs to MultiROM
1. Boot again to Recovery and this time go to Advanced >MultiROM > Add ROM.
2. Select the ROM you want and click install. You need at least 700 MB of free space for each ROM.
3. If you want to change it later, go to Advanced > MultiROM > List ROMs and select the file you want.
This was the tutorial of how to install MultiROM on your OnePlus One and boot multiple ROMs at the same time. Credits go the original developer who made this possible. Check the original thread here.