This feature limited the app to multi-boot two ROMs with different kernels like booting ICS and GB, since both have different kernel tree.
But this is not an issue anymore, as a newly inspired user arnab321 modified this specific app and indulged the capability to boot two different ROMs with different kernels. This seems to be a piece of huge news for those who already loved this app (mod).
Features of Multi-ROM Manager
1. ROM Switching: The app has a unique feature to change kernel, as in by backing up the boot.img and flashing them. (The flashing takes least time, about 1 min for GB based ROMs and maybe a little more for ICS/JB based ROM)
2. ROM Zip Modder: This feature is for the ease of the users, so now you just have to select the zip you want to flash to SD-Ext and this app will amend the updater-script and make it directly flashable to your SD-Ext. Also, the modified ROM.zip will have the Multi-ROM embedded, so there won't be any need to install it again)
Limitations, that must be kept in mind:1. ROMs must be for the same baseband. 2. It will be slower than the internal memory. (However, if you have a high-class memory card, it shall be as fast as the internal memory ROM)
Requirements for using this mod and the app:1. Ext4/Ext2/Ext3 partition on SDcard big enough to hold all files from /system and /data, which is from 170mb to 400mb (depends on ROM and apps installed), so I think 512mb partition is minimum (if its 90% or so free). 2. Modified recovery (AmonRA and CWM available) 3. A kernel with ext2/3/4 support
Download Multi-ROM ManagerMulti-ROM v19 Tasssadar's Sources arnab321's app sources
Instructions to Use Multi-ROM Manager
1. Guess you already have an ext partition on sdcard. (else create it from recovery, GParted, or any partitioning software). A typical ROM takes about 200-250mb if you keep minimal apps.
2. I also assume that you have Multi-ROM (not this app) installed. Else simply use the app's "check for updates" to install Multi-ROM. (Or maybe download the flashable zip from tasssadar.github.com )
3. backup your current boot image with the app. (I'm calling this backup as rom1.img)
4. Steps to flash a new ROM to sdcard:
- Use the "prepare zip" menu of the app, choose the ROM zip you want to flash on sdcard. (Sense ROMs will not work)
- It will take some time as it extracts, modifies and repacks the zip. When the preview of the updater script is shown, just press "save".
- After the progress bar completes, you will see the "embedding Multi-ROM" screen. If you are a first time user and see a prompt about choosing Multi-ROM.zip before that screen, just choose "download from the internet".
- At the "choose boot location" prompt, select "sdcard".
- The boot image of the Rom will be stored as "tmp_boot.img" (all boot image backups are stored in /sdcard/multirom/). Just rename it to something meaningful with a file manager. Let's say I renamed it to Rom2.omg. You will need this to boot into the ROM later.
- Go to recovery and flash the zip. (The modded zip will have the prefix "mrom-").
- Reboot. Your Rom in sdcard should boot now.
5. Switching Roms:
- To switch to Rom on the internal memory, go to "backup/restore boot image" on the app, select rom1.omg, choose "internal memory" and reboot.
- To switch to ROM on sdcard, do the same thing with rom2.img and choose "sdcard".