[MOD][FEB 10] MultiROM v33


Inactive Recognized Developer
Dec 31, 2010

MultiROM is one-of-a-kind multi-boot mod for Nexus 7. It can boot any Android ROM as well as other systems like Ubuntu Touch, Plasma Active, Bohdi Linux or WebOS port.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, daily prebuilt image files to install Ubuntu Touch and MultiROM even has its own installer system, which can be used to ship other Linux-based systems.

* Multiboot any number of Android ROMs
* Restore nandroid backup as secondary ROM
* Use for example Ubuntu Touch or Desktop alongside with Android, without the need of device formatting
* Boot from USB drive attached via OTG cable

You can also watch a video which shows it in action.


It _is_ dangerous. This whole thing is basically one giant hack - none of these systems are made with multibooting in mind. It is messing with boot sector and data partition. 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.​

1. Via MultiROM Manager app
This is the easiest way to install everything MultiROM needs. Install the app and select MultiROM and recovery on the Install/Update card. If the Status card says Kernel: doesn't have kexec-hardboot patch! in red letters, you have to install also patched kernel - either select one on the Install/Update card or get some 3rd-party kernel here on XDA. You are chosing kernel for your primary ROM, not any of your (future) secondary ROMs, so select the version accordingly.
Press "Install" on the Install/Update card to start the installation.

2. Manual 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. There is also an awesome article on Linux Journal.

Note 1: There have been reports that (not only) MultiROM does not work properly with older bootloaders. Update it to version 4.13 or newer in case you have problems.

MultiROM has 3 parts you need to install:

  • MultiROM (multirom_vXX_n7-signed.zip) - download the ZIP file from second post and flash it in recovery.
  • Modified recovery (TWRP_multirom_n7_YYYYMMDD.img) - download the IMG file from second post and use fastboot or Flashify app to flash it.
  • Patched kernel - You can use either one of the stock ones in second post or third-party kernels which include the patch, you can see list in the second post. Download the ZIP file and flash it in recovery.
You current rom will not be erased by the installation.
Download links are in the second post.

Adding ROMs

1. Android
Go to recovery, select Advanced -> MultiROM -> Add ROM. Select the ROM's zip file and confirm. As for the space, clean installation of stock 4.2 after first boot (with dalvik cache generated and connected to google account) takes 676mb of space.​

2. Ubuntu Touch
Use the MultiROM Manager app to install Ubuntu Touch.

Ubuntu Touch is in development - MultiROM will have to be updated to keep up with future changes in Ubuntu, so there's a good chance this method stops working after a while and I'll have to fix it.

3. Ubuntu Desktop
Ubuntu desktop for Nexus 7 has been discontinued and is no longer updated. 13.04 is the last release.
Download Ubuntu 13.04 image from here. Put the image in the memory of N7 or to USB flash drive and go to recovery. Select Advanced -> MultiROM -> Add ROM and choose "Ubuntu" as ROM type. Then select the Ubuntu's image and confirm. Clean installation of Ubuntu is 1.5gb big, and takes a while (10 minutes?) to install.
The first boot takes a bit longer, and 13.04 stays a while (30-60s) in console ("Enter login:") before the GUI shows up, so just wait a while.
Ubuntu ROM must not have spaces in name!
Using Ubuntu on N7, Frequently Asked Questions

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, so installation of Ubuntu to 4Gb image on my pretty fast USB drive takes about 20 minutes.
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.
  • In some cases, you might need to flash patched kernel - get coresponding patched kernel version from second post and flash it to the secondary ROM sama way you flashed ROM's ZIP file.

Explanation of recovery menus

Main menu
- Add ROM - add ROM to boot
- List ROMs - list installed ROMs and manage them
- Inject boot.img file - When you download for example kernel, which is distrubuted as whole boot.img (eg. franco kernel), you have to use this option on it, otherwise you would lose MultiROM.
- Inject curr. boot sector - Use this option if MultiROM does not show up on boot, for example after kernel installation.
- Settings - well, settings.

Manage ROM
- Rename, delete - I believe these are obvious
- Flash ZIP (only Android ROMs) - flash ZIP to the ROM, for example gapps
- Add/replace boot.img - replaces boot.img used by this ROM, this is more like developer option.
- Re-patch init - this is available only for ubuntu. Use it when ubuntu cannot find root partition, ie. after apt-get upgrade which changed the init script.​

Source code


I'd be glad if you could spare a few bucks. You can use either paypal or Bitcoins, my address is 172RccLB2ffSnJyYwjYbUD3Nx4QX3R8Ris

Thanks to all donors, it is much appreciated :)

XDA:DevDB Information
MultiROM, a Tool/Utility for the Nexus 7


Version Information
Status: Stable
Current Stable Version: v16a
Stable Release Date: 2013-10-22

Created 2013-07-30
Last Updated 2013-10-22


Last edited:


Inactive Recognized Developer
Dec 31, 2010

1. Main downloads

MultiROM: multirom-20160207-v33-grouper.zip
Modified recovery (based on TWRP): TWRP_multirom_grouper_20160210.img (grouper) or TWRP_multirom_tilapia_20160210.img (tilapia)
MultiROM Manager Android app: Google Play or link to APK

Kernel w/ kexec-hardboot patch (Stock 4.1): kernel_kexec_grouper_41-3.zip
Kernel w/ kexec-hardboot patch (Stock 4.2): kernel_kexec_grouper_42-3.zip
Kernel w/ kexec-hardboot patch (Stock 4.2.2): kernel_kexec_grouper_422-2.zip
Kernel w/ kexec-hardboot patch (Stock 4.3): kernel_kexec_grouper_430-2.zip
Kernel w/ kexec-hardboot patch (Stock 4.4): kernel_kexec_grouper_440.zip
Kernel w/ kexec-hardboot patch (Stock 4.4.1 and 4.4.2): kernel_kexec_grouper_441.zip
Kernel w/ kexec-hardboot patch (Stock 4.4.3 and 4.4.4): kernel_kexec_grouper_443.zip
Kernel w/ kexec-hardboot patch (Stock 5.0): kernel_kexec_grouper_50_final.zip
Kernel w/ kexec-hardboot patch (Stock 5.0.2): kernel_kexec_grouper_502.zip
Kernel w/ kexec-hardboot patch (Stock 5.1 and 5.1.1): kernel_kexec_grouper_510.zip
Kernel w/ kexec-hardboot patch (CM 10.1): kernel_kexec_grouper_cm101-5.zip
Kernel w/ kexec-hardboot patch (CM 10.2): kernel_kexec_grouper_cm102-2.zip
Kernel w/ kexec-hardboot patch (CM 11 (4.4 - 4.4.2)): kernel_kexec_grouper_cm11.zip
Kernel w/ kexec-hardboot patch (CM 11 (4.4.3 - 4.4.4)): kernel_kexec_grouper_cm11-2-87193876fd.zip
Kernel w/ kexec-hardboot patch (CM 12): kernel_kexec_grouper_cm12-1-124dbe573f.zip
Kernel w/ kexec-hardboot patch (CM 12.1): kernel_kexec_grouper_cm121-01-5e0fa481d7.zip
You need to have kernel with kexec-hardboot patch only in your primary ROM!

Mirror: http://d-h.st/users/tassadar

2. third-party kernels with kexec-hardboot patch

motley - http://forum.xda-developers.com/showthread.php?t=1775798
intersectRaven - http://forum.xda-developers.com/showthread.php?t=2065901
M-kernel - http://forum.xda-developers.com/showthread.php?t=1937146
Trinity Seven - http://forum.xda-developers.com/showthread.php?t=1788759
Omega 3 kernel - http://forum.xda-developers.com/showthread.php?t=2093175
vorcers' kernel - http://forum.xda-developers.com/showthread.php?t=2107224
franco.Kernel - http://forum.xda-developers.com/showthread.php?t=1823671
DMORE.Kernel - http://forum.xda-developers.com/showthread.php?t=2173411
Timur's Kernel (USB host power management) - http://rootzwiki.com/topic/37755-ti...host-power-management-usb-audio/#entry1137968
Faux's kernel - http://forum.xda-developers.com/showthread.php?t=1804374
Oxydo kernel - http://forum.xda-developers.com/showthread.php?t=2373410

3. Linux ROMs (Bohdi, Plasma Active, WebOS packed for MultiROM)

You can find these systems in separate thread: forum.xda-developers.com/showthread.php?t=2093797

4. Uninstaller

MultiROM uninstaller: multirom_uninstaller-2.zip
Flash this ZIP file to remove MultiROM from your device. It will erase all secondary ROMs. If you don't want MultiROM menus in recovery, re-flash clean TWRP, but it is not needed - those menus don't do anything if MultiROM is not installed.

5. Flashable factory images ZIPs
I usually release flashable ZIP files based on new factory images from Google, so that you can have clean stock ROM as a secondary system in MultiROM. They are not rooted, no anything, except for occasional small tweaks to make rooting with SuperSU possible. You can find them in this folder on basketbuild or dev-host.

MultiROM v33
* Updates for Android 6.0 compatibility

MultiROM v32a
* Fix pattern encryption password incorrectly reporting "invalid password"
  when the pattern overlaps itself

MultiROM v32
* Minor GUI improvements
* Support for device encryption (with Android-based secondary ROMs only). See
  FAQ in this device's XDA thread for more info.
* Bunch of ROM compatibility fixes

MultiROM v31
* Add support for "multimount" fstab (fixes CM12)
* Support interlaced PNGs (fixes wrongly rendered icons in boot manager, e.g.
  the L icon)

MultiROM v30
* Fix logs generated by the "emergency reboot" screen, they were incomplete

MultiROM v29
* Implement "autoboot if no key pressed" mode - the boot manager won't show up
  unless you hold down a volume down button during boot. Must be enabled in
* Android 5.0 preview related tweaks

MultiROM v28
* Fix freezes in the boot manager
* You can now swipe between the tabs in the boot manager
* Minor UI adjustments
* SailfishOS support (for certain devices)

MultiROM v27
* Redesign the boot manager GUI. Looks much better now.
* Fix separate radio.img not working on Android L preview ROMs
* Fix issues with unaccessible /sdcard on Android L preview. Do NOT run
  restorecon manually on /data/media, ever - it breaks MultiROM!
* Workaround bug which caused franco.Kernel on N5 to break secondary ROM's
* Update Ubuntu Touch init scripts
* Use power+volume down (you have to press power first!) to save screenshots.
  They are now PNG images and are saved to /sdcard/Pictures/Screenshots/.

MultiROM v26
* Fix boot into secondary ROM from the MultiROM Manager app broken in v25

MultiROM v25
* Add support for the Android L preview
* Misc F2FS fixes

MultiROM v24
* Add F2FS support
* Show icons in ROM list, configurable via MultiROM Manager app
* Improve compatibility with different ROMs and kernels when booting a ROM
  from the Android app

MultiROM v23
* Fix compatibility with Ubuntu Touch rev 290 and higher. If your Ubuntu
  installation won't boot, go to recovery and use "Re-patch init" option in
  Advanced -> MultiROM -> List ROMs -> *ubuntu*.

MultiROM v22b
* Mount the real /data partition to folder /android/realdata in Ubuntu Touch,
  enabling sharing data between Android and Ubuntu Touch. See
  [url]http://bit.ly/ut_sharing[/url] for more info.

MultiROM v22a
* Fix hardware keys not working for some users
* Update Ubuntu Touch patches

MultiROM v22
* Fix linux-type ROMs (Ubuntu Touch) failing to boot for some users

MultiROM v21
* Revert "mount /system in secondary ROMs read-only" - if done so, SuperSU
  breaks the boot.

MultiROM v20
* Support booting ROMs directly from Manager App
* Fix FCs on CyanogenMod-based ROMs
* Fix support for USB drives formatted with NTFS, broken in v17
* Mount /system in secondary ROMs read-only

MultiROM v19
* Implement "boot the last ROM" auto-boot type

MultiROM v18
* Fix silent-but-unpleasant crash with exFAT

MultiROM v17
* Changes to support MultiROM Manager app
* Add support for exFAT

MultiROM v16a
* Fix kexec not working on some kernels

MultiROM v16
* Add overscroll bounceback effect to rom list
* Add support for controling via physical keys
* Bunch of under-the-hood changes for mako and m7 support

MultiROM v15
* Fix cmdline handling for kexec, doesn't change anything for grouper, just to
  have the same version for both flo and grouper (no need to update)

MultiROM v14
* Find and change correct fstab (fixes freezes on boot)
* Mount /realdata without nosuid (fixes no root on 4.1 and 4.2 ROMs)
* Use libbootimg to work with boot.img files

MultiROM v13
* Partial rewrite of the codebase to make it compatible with multiple devices
* Add run-on-boot scripts (for advanced users who know linux and bash, see
* Use libbootimg to work with boot.img files

MultiROM v12a
* Detect kexec-hardboot patch in kernel even if /proc/config.gz is not

MultiROM v12
* Implement screen rotation and 1280x800 theme
* Fix auto-boot option
* Fix listview's fast scrollbar behavior

MultiROM v11
* Option to hide Internal ROM
* Option to rename Internal ROM
* Support for Ubuntu Touch

MultiROM v10
* Non-error message boxes aren't red now
* Add possibility to switch between several color themes, go to misc tab and
  try it out
* New MultiROM installer format
* Add "discard" option to /data mounting
* Add battery status to misc tab (bottom right corner)
* Add brightness setting
* Implement ADB

MultiROM v9
* Make it compatible with LZ4 ramdisk compression
* Improve touch-related code. You should not get anymore phantom button
  presses nor listview freezes

MultiROM v8
* Fix kexec-hardboot with new bootloader v4.18
* Search for already present USB drives on start
* Centre "MultiROM" title in main UI

MultiROM v7
* Correctly boot Ubuntu after recent kernel update. Read this post:
* Remove specific support for Ubuntu - it is now handled as "generic linux"
  (with rom_info.txt file). Nothing should change for the users
* Sort ROMs alphabetically
* Add "progress dots" to USB screen, so that user knows that it is doing
* Recovery was also updated, don't forget to flash it

MultiROM v6
* Properly check for kexec-hardboot patch in kernel
* Internal" is always first in ROM list now, as originally intended
* Much more logging for kexec-related stuff
* Print last 50 lines of klog to "Emergency reboot" screen

MultiROM v5-2
* Fix ubuntu
* MultiROM still says it's v5. I did not change the version number because it
  is literally one character fix.

MultiROM v5
* Support for ROMs with configuration file. This makes porting
  Ubuntu/plasma/webos/anything much more easier. See the third post.
* MultiROM will no longer let you boot Ubuntu ROM if it's name contains
  spaces, because the boot would fail.

MultiROM v4
* Fix GPS on ROMs other than Internal
* Minor UI changes

MultiROM v3
* Switch to Ubuntu 13.04. Version 12.10 is no longer supported
* Switch to kexec-hardboot based multi-booting. Read the first post.
* Add support for booting from USB drive
* MediaScanner no longer scans /sdcard/multirom, which means no useless
  battery drain
* Recovery was updated, make sure to flash it, too.

MultiROM v2
* Add support for Ubuntu on 3G version of Nexus 7
* Fix some issues with 4.2 ROMs
* Recovery was updated, make sure to flash it, too.

MultiROM v1
* Initial version

* Fix ZIP selector being set to wrong storage after flashing ZIP to a
  secondary ROM

* Update to TWRP 3.0.0 (big thanks to nkk71 for doing most of the work)
* Use Material theme made by z31s1g - thanks!
* Fixes for 6.0 compatibility
* Fixes for SuperSU compatibility. Use BETA 2.67-20160203160253 (
  [url]http://bit.ly/m_su[/url] ) or newer!

* Update to TWRP 2.8.7

* Fix installation of CM-based ZIP files
* Add "duplicate ROM" option to "Swap ROMs" page
* Running "restorecon -R /data" while in recovery will no longer break
  secondary ROMs

* Fix support for SuperSU 2.47 Beta and higher

* Update to TWRP 2.8.6
* Added "restorecon" option to secondary ROMs (in MultiROM -> List ROMs),
  should be used to fix broken SELinux contexts, which can be causing
  bootloops of secondary ROMs
* Bunch of ROM compatibility fixes - recovery now uses entirely new way to
  inject ZIP installation files, which should be much more robust and reliable
* Big ZIPs (> 450MB) are no longer permanently modified when flashed as
  secondary ROMs
* Fix sideloading of big ZIP files (> 450MB) into secondary ROMs

* Update to TWRP 2.8.5
* Fix support for ROMs containing a supersu.zip in their installation file
  (e.g. AICP)

* Fix "Swap ROMs" feature after the last update

* Update to TWRP 2.8.4
* Lots of ZIP compatibility fixes (e.g. for CM 12)

* Support for ZIP files which are using the new 'block_image_update' command
  (e.g. SimpleAOSP ROM)

* Update to TWRP 2.8.1

* Update autoboot settings for MultiROM v29

* Update with changes from upstream version: fix a bug that causes
  weird graphics glitches and touch issues

* Update to TWRP 2.8.0
* Fix adding ROMs from backup to a FAT32 USB drives
* Remove "share kernel with internal?" from "Add ROM" page, there is usually
  no reason to use it anymore and it might be confusing to figure out what it
  actually does. You can still get the same behavior by clicking "Remove
  boot.img" on the List ROMs -> *rom name* page.

* Remove Ubuntu Touch installation, installing via recovery is deprecated
* Add SailfishOS installation (only for supported devices)

* Show secondary ROM's name in the title bar while executing it's script (e.g.
  during OTA update)
* Update Ubuntu Touch updater
* Fix failure to swap ROMs if it contains filenames starting with a dot
* Fix add ROM from a backup producing unbootable ROM with Android L preview
* Add option to remove radio.img from secondary ROMs
* Add config options for MultiROM v27

* Update to TWRP 2.7.1
* Hide misleading "Mount: Unable to find partition for path '/data'" message
  which appeared during secondary ROM installation, it is not _actually_ an
* Fix installation of non-Android systems to USB drives

* Fix installation of bigger (>350MB) ZIPs as secondary ROMs

* Fix installation of Ubuntu Desktop

* Fix crash during settings loading, causing a bootloop with certain settings

* Add F2FS support
* Add tool to switch F2FS<->ext4 to Advanced menu
* Fix problems with backups introduced by TWRP 2.7.0

* Update to TWRP 2.7.0
* Remove "save" button from MultiROM settings page, it is saved automatically
* Some rendering optimizations, resulting in noticeably higher FPS in recovery

* Fix GPG signature verification of Ubuntu Touch installation files
* Add support for mice connected via USB-OTG
* Fixup scrollbar behaviour in file list

* Fix installing ROMs to USB drive
* Fix ZIP verification
* Support ZIP verification for secondary ROMs

* Support OTA updates on secondary ROMs (tested with omni)
* Add "Swap ROMs" feature
* Implement "boot the last ROM" auto-boot type
* Many bugfixes

10.11.2013 - 01
* Fix some mounting issues when using ntfs or exFAT

* Add exFAT support
* Support system-image based Ubuntu Touch installation
* Support Ubuntu Touch OTA updates, if Ubuntu is installed
  via MultiROM manager app

* Fix SuperSU reporting "failed" when flashed to secondary ROM
  and completely borking the MultiROM part for any subsequent
  uses of "Flash ZIP" or "Backup" option

* Automatically inject boot sector with MultiROM
  after ZIP installation or ADB sideload. Can be
  turned off on "confirm flash" or "ADB sideload"

* Support 'adb sideload' when adding ROMs
* Support rotation while using custom recovery theme

* Don't display unsupported systems in "Add ROM" menu

* Use libbootimg to work with boot.img files

* Fix custom theme support

* Partial rewrite of the codebase to make it compatible with multiple devices
* Add option to backup secondary ROMs
* Don't show "Flash ZIP" option for Ubuntu Touch ROM, it is not an Android

* Update to TWRP
* Fix Ubuntu desktop image decompression

* Update to TWRP
* Temporarily removed Timur's USB kernel, because it is not
  4.3-compatible and I can't find sources

* Clean rebuild of the recovery, I probably forgot to do that last time
  and it wouldn't boot on some tilapia devices. No function changes.

* Fix updater-script incompatibilities for some ROMs (e.g. PAC-Man)

* Fix deletion of 4.3 ROMs with new SuperSU version installed

* Don't ignore format("/system"); when flashing ZIPs to secondary ROMs,
  this should fix updating secondary ROMs, particulary from 4.2 to 4.3
* Some fixes for 4.3 ROMs
* Add "remove boot.img" option to Android ROMs

* Fix crash when installing Android ROM with kernel sharing enabled

* Add rotation option to MultiROM settings
* Properly handle kernel flashing for Android ROMs:
  you can now flash kernel via "Flash ZIP" option in "List ROMs" menu,
  Aroma installer should work properly
* Fix ZIP flashing for 3G version of Nexus 7

* Update to TWRP
* Support for screen rotation, Settings -> Screen
* Support for Ubuntu Touch
* Added options from MultiROM v11 to hide or rename Internal ROM
* MultiROM Settings menu was reorganized
* MultiROM options added to landscape layout
* Recovery now has Timur's USB host kernel

* Fix "Add ROM" option not properly installing /data partition from
  backup, if the backup is bigger than 1.5gb
* Make names of ROMs created from Android Backup prettier

* Update to TWRP

* Add support for MultiROM installer format
* Add new MultiROM settings (brightness, adb)

* Updated to TWRP
* Add support for LZ4 & LZMA ramdisk compression
* Add some handy buttons to "flash complete" page,
  thanks ikslawlok for suggestion

* Fix freeze when selecting ROM in "Add ROM" option
  in MultiROM menu

* Updated to TWRP

* Fix recovery kernel, so that you can boot linux ROMs even if
  kernel in internal memory has older kexec-hardboot patch
* Enable brightness settings from TWRP

* Updated to TWRP
* Add fast scrollbar to fileselectors
* Voldown to turn off screen ("sleep" mode)

* Fix Ubuntu Touch installation with
  combination of 4.2 as Internal ROM

* Don't copy the ZIP to RAM while flashing ZIPs bigger
  than 450 MB (currently only Ubuntu touch) in "Add ROM"
  or "Flash ZIP" options. This prevents crash which would appear
  due to low memory, but also means that these ZIP files
  will be modified, which makes them unusable outside MultiROM
  after flashing.
* Add Ubuntu touch support

* Update to TWRP
* Don't reset ROMs location in "List ROMs" when going back
  from managing ROM to the ROM list
* Fix recovery crash when there is too deep directory structure
  in /data, thanks rifraf for debugging this

* Update to TWRP
* Properly disable flash-kernel during Ubuntu installation.
  This is important fix, because without it, Ubuntu
  can rewrite your boot.img.
* Add option to wipe /data, /cache and dalvik-cache
  of secondary Android ROMs
* Use gnutar binary compiled specifically for tegra 3,
  means faster installation of Ubuntu
* Add "pressed" effect to all buttons, so that you know
  if you pressed it or not.
* When installing Android ROM from ZIP which does not have
  boot.img (armoma installer...), try to use current boot sector
  instead of boot.img. The ROM may not boot, so you should always
  add boot.img which is compatible to the ZIP file.
* Update to keep up with MultiROM v7

* Fix "Add ROM" for backups in internal memory
* Update TWRP to
* Add option to Add ROM from backups
* Should be able to flash ZIP files for both grouper and tilapia

* Update to support MultiROM v3

* Fix "flash zip" option for ROMs without whitespace in name. I've
  accidentally broke it in previous update, sorry :/

* Fix "flash zip" option for ROMs with whitespace in name

* Add Ubuntu support for Nexus 7 3G

* Initial version
Last edited:


Inactive Recognized Developer
Dec 31, 2010
FAQ and other notes
Device encryption
Since v32, MultiROM supports encryption on this device (it has to be added for each device separately). It works only with Android-based secondary ROMs and the secondary ROMs don't know the device is encrypted, so they would allow you to encrypt the device again - do not do that. If you're using password, pin or pattern for the encryption, MultiROM will ask you for the password on boot. If you're booting the primary ROM, then Android will ask you for the password _again_ - unfortunately, there is no way for me to pass the "unencrypted" status to Android. If you're booting secondary ROM, MultiROM will ask you for the password again after the reboot - that's because I have to unencrypt the /data partition after the ROM's kernel is loaded.

I could omit the second password prompt when booting secondary ROM by temporarily saving the password somewhere, but that's obviously unsafe. So is using encryption with unlocked device though, so I might add this later.​

About security
In order to make multi-booting possible, MultiROM has to sacrifice some security measures. Firstly, on secondary Android ROMs, /system is not mounted read-only. While there are other things preventing malicious software from messing with /system, this might potentialy make it easier for such software to attack that system.​

What do the ROMs share?
All ROMs are separate, except /sdcard, which is shared between all Android ROMs.​

How many ROMs can I have?/Where are the ROMs stored?
You can have as many ROMs as you can fit in your /sdcard. All the ROMs are stored in /sdcard/multirom/roms or on an USB drive. This folder is unaccessible in Android, to prevent mediascanner from scanning it. You can either in recovery, or obtain root and go to /data/media/0/multirom/roms.

Can I have different versions of Android working alongside
Yes. As long as you select "Don't shere kernel" when installing the secondary ROM, the systems are separated.​

MultiROM recovery says it's Why isn't it updated to 2.6.3.*highernumber*?
It is, it just shows wrong version.​

The menu with all the ROMs won't show up during boot, how to fix it?
Either re-flash the MultiROM zip or go to recovery, Advanced -> MultiROM -> Inject curr. boot sector.

The reason for this is that something rewrote your boot.img, which happens for example when you flash a kernel. MultiROM's boot menu is part of the boot image, so it has to be added into it again.

Will you port MultiROM to device X?
No, probably. I won't port MultiROM to any device I don't own, because it is very difficult to provide the level of support I want to provide if I can't test things myself, as proven by the Nexus 4 port. I'd like to support more devices, but it is also very unsatisfying to work on code for device I don't have - I invest hours upon hours of time for free into it, and then I can't even see it running on the device, so...why..bother..?
I'll probably keep buying Nexus devices and keep porting MultiROM to those myself, but I can't buy every single device - I'm still a student, all my existing devices were bought using some kind of money grant or donations from users.
But, you can port it yourself, the wiki should give you at least some idea how to do that: https://github.com/Tasssadar/multirom/wiki/Porting-MultiROM
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Aug 16, 2012
Has anyone done this yet? I'm a little nervous to try this. I really want to though just don't want to be the first as im still relatively new to adb

sent from my paranoid nexus 7


Senior Member
May 23, 2012
Chicago, IL
I installed Multirom successfully, and used the boot screen and everything. I installed the ubuntu rootfs.img and it seems to be taking a long time on "Preparing the root file system, please wait, this will take a few minutes..." I had just under 2 GB free when I installed it, is that enough, used the Nexus 7 16 GB image.

EDIT: I just saw the post above, where are you getting you need 2-3 GB to install? I think Im going on 10 minutes...I may reboot to Internal(Android 4.2 AOKP) to free some storage space, delete a game or something, and start over installing Ubuntu.

EDIT 2: You a long list of No space left on device messages for a list of files, gotta start over.
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Inactive Recognized Developer
Dec 31, 2010
It takes a while to install ubuntu, it extracts about 600mb archive, that means you need the space for archive itself and the extracted data (archive is erased at the end of the process). I say 3gb of free space just to be sure.

If it fails because it does not have enough space (you will notice the spam of "no space left" messages), just reboot to your internal ROM, then reboot to recovery, delete the ROM and try again with more free space.
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Senior Member
Aug 11, 2012
My understanding of Ubuntu is that it can run microsoft office through the use of a virtual machine, does this support the use of a virtual machine?


Senior Member
May 22, 2007
My friend, you rules!, you´re the boss!, the big cheese, Big Kahuna!, etc, etc, etc.

Since I heard about Ubuntu for N7, I've been looking for a solution like that for I have both distro in my tablet. Now, thank to you, that is possible!.

Thank you for sharing, keep walking!!.


P.S.: Btw, works terrific with my 4.2 rooted stock ROM in my 8GB N7


Senior Member
Jul 19, 2012
Stupid question...I clicked on the Ubuntu link and tried to download the 8gb Nexus image but it doesn't download. It opens it up. No download. Am I doing something wrong?

Sent from my Nexus 7 using XDA Premium HD app


Senior Member
May 23, 2012
Chicago, IL
I got it working with AOKP 4.2 and Ubuntu, and I'm going to add PA Beta 3 once it gets re-uploaded. 2 android ROMs and Ubuntu! Awesome!

Sent from my Nexus 7 using Tapatalk HD