[Mi 3 Android Development] vasishath:
Introduction

MultiROM for the Xiaomi Mi3 and Mi4

MultiROM is one-of-a-kind multi-boot mod for Xiaomi Mi3. It can boot any Android ROM as well as other systems like Ubuntu Touch, once they are ported to that device. Besides booting from device's internal memory, MultiROM can boot from USB drive connected to the device via OTG cable. The main part of MultiROM is a boot manager, which appears every time your device starts and lets you choose ROM to boot. You can see how it looks on the left image below and in gallery. ROMs are installed and managed via modified TWRP recovery. You can use standard ZIP files to install secondary Android ROMs and MultiROM even has its own installer system, which can be used to ship other Linux-based systems.

Features:

* Multiboot any number of Android ROMs

* Restore nandroid backup as secondary ROM

* Boot from USB drive attached via OTG cable

Warning!

It _is_ dangerous. This whole thing is basically one giant hack - none of these systems are made with multibooting in mind. It is no longer messing with data partition or boot sector, but it is possible that something goes wrong and you will have to flash factory images again. Make backups. Always.

Installation

Firstly, there are videos on youtube. If you want, just search for "MultiROM installation" on youtube and watch those, big thanks to all who made them.

MultiROM has 2 parts you need to install:

Modified recovery - download the IMG file from second post and use fastboot or Flashify app to flash it.

MultiROM - download the ZIP file from second post and flash it in recovery.

You current rom will not be erased by the installation.

Download links will be uploaded shortly in second post.

Adding ROMs

Go to recovery, select Advanced -> MultiROM -> Add ROM. Select the ROM's zip file and confirm. As for the space, clean installation of a rom after first boot (with dalvik cache generated and connected to google account) takes approx 700mb of space.

Attention : MIUI does not work with multirom, so dont flash it.

Using USB drive

During installation, recovery lets you select install location. Plug in the USB drive, wait a while and press "refresh" so that it shows partitions on the USB drive. You just select the location (extX, NTFS and FAT32 partitions are supported) and proceed with the installation.

If you wanna use other than default FAT32 partition, just format it in PC. If you don't know how/don't know where to find out how, you probably should not try installing MultiROM.

If you are installing to NTFS or FAT32 partition, recovery asks you to set image size for all the partitions - this cannot be easilly changed afterward, so choose carefully. FAT32 is limited to maximum of 4095MB per image - it is limitation of the filesystem, I can do nothing about that.

Installation to USB drives takes a bit longer, because the flash drive is (usually) slower and it needs to create the images.

Enumerating USB drive can take a while in MultiROM menu, so when you press the "USB" button in MultiROM, wait a while (max. 30-45s) until it searches the USB drive. It does it by itself, no need to press something, just wait.

Updating/changing ROMs

1. Primary ROM (Internal)

Flash ROM's ZIP file as usual, do factory reset if needed (it won't erase secondary ROMs)

Go to Advanced -> MultiROM in recovery and do Inject curr. boot sector.

2. Secondary Android ROMs

If you want to change the ROM, delete it and add new one. To update ROM, follow these steps:

Go to Advanced -> MultiROM -> List ROMs and select the ROM you want to update.

Select "Flash ZIP" and flash ROM's ZIP file.

Source code

MultiROM - https://github.com/Tasssadar/multirom/tree/master (branch master)

Modified TWRP - https://github.com/Tasssadar/Team-Win-Recovery-Project (branch master)

Thanks a lot to Tasssadar for creating this awesome utility.

Thanks to [MENTION=5093942]KINGbabasula[/MENTION] for this thread template and [MENTION=5334172]Gnome[/MENTION] for his stuxnet kernel

Thanks to [MENTION=5857684]TheStrix[/MENTION], [MENTION=5093942]KINGbabasula[/MENTION], [MENTION=5880909]rooque[/MENTION] for their help in porting this to our device.

Special thanks to [MENTION=5162591]Shahan_mik3[/MENTION] without whom i wouldn't have started developing roms and stuff

ABANDONED