Black God

Mounting /system partition in read-write mode in Android

Any hacker needs full access to the system files to play with the system. Andoid /system partition is read-only by default. Here is an HOWTO to mount it in read-write mode. It is assumed that you have installed android SDK in your workstation. We use adb tool in tools directory of SDK.

1. Identifying the /system partition device file: Follow the sample session.

C:\android-sdk-windows-1.1_r1\tools>adb shell

$ su

# mount
rootfs / rootfs ro 0 0
tmpfs /dev tmpfs rw,mode=755 0 0
devpts /dev/pts devpts rw,mode=600 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
tmpfs /sqlite_stmt_journals tmpfs rw,size=4096k 0 0
/dev/block/mtdblock3 /system yaffs2 ro 0 0
/dev/block/mtdblock5 /data yaffs2 rw,nosuid,nodev 0 0
/dev/block/mtdblock4 /cache yaffs2 rw,nosuid,nodev 0 0
/dev/block/mmcblk0p1 /sdcard vfat rw,dirsync,nosuid,nodev,noexec,uid=1000,gid=1000,fmask=0711,dmask=0700,codepage=cp437,iocharset=iso8859-1,utf8 0 0

/dev/block/mtdblock3 is the /system partition device file.

2. Remounting the /system in read-write mode:

# mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system


3. If necessary set read-write permission to any directory under /system. Don’t forget to revert back once you get what you are intended to do.

# chmod 777 /system/fonts

4. Exit the hacker session

# exit

$ exit

Enjoy the freedom of /system.

24 comments for “Mounting /system partition in read-write mode in Android

  1. Dog
    June 5, 2012 at 12:41 pm

    That might be useful. Im trying to get market working on android x86

  2. Dasi Rajesh89
    November 11, 2011 at 11:28 am

    Hi

    Are this commands applicable in the windows OS
    coz I’m facing some problem accessing the permission

  3. vineela
    November 1, 2011 at 10:07 am

    I have a gingerbread android tablet, I follow the steps above, instead of the red line on step 1 I got:
    /dev/block/mtdblock4 /system cramfs ro 0 0
    so I mount with those values, then i tried to chmod the system folder, I receive the error message:
    Unable to chmod /system: Read-only file system
    Why does it failed? Please help me

  4. Peacekeeper72
    October 19, 2011 at 3:21 am

    where does it get mounted to? its not under My Computer / drive list

  5. Marc Schlaich
    July 28, 2011 at 10:29 am

    Try this:
    # mount -o remount,rw /system

  6. April 25, 2011 at 10:20 pm

    this is totatlly awesome ! 10x

    but i wanted to ask something,

    when i type n enter “adb push GoogleServicesFramework.apk /system/app” i got the failed msg couse of permission, but i did chmod 777 :S

    the device htc desire btw

    thanks again !

  7. Noam
    February 5, 2011 at 2:35 pm

    I have a noname android tablet, I follow the steps above, instead of the red line on step 1 I got:
    /dev/block/mtdblock4 /system cramfs ro 0 0
    so I mount with those values, then i tried to chmod the fonts folder, I receive the error message:
    Unable to chmod /system/fonts: Read-only file system
    Why does it failed? Please help

  8. Samuel DH
    December 11, 2010 at 5:34 am

    WHen i type in C:\android-sdk-windows\tools>adb shell $ su # mount, it says “not recognized as an operable program or file. If i put C:\android-sdk-windows\tools\adb.exe shell $ su # mount, it says $: not found. Help!

    • December 11, 2010 at 9:27 am

      1. Replace “C:\android-sdk-windows-1.1_r1″ with your SDK installation path if necessary. The following is the command to invoke adb in shell mode.

      C:\android-sdk-windows-1.1_r1\tools>adb shell

      2. Once you get $ prompt, enter su command to get root user shell. You will get # prompt.

      $ su

      3. Now run mount command

      # mount

  9. August 15, 2010 at 6:03 am

    Even as I love a physical keyboard, after handling the Samsung Captivate for roughly quarter-hour, it is hard to go back. Right now I am debating whether or not to go to Verizon for the Droid X, pass to Dash for the EVO, or stay with AT&T for the Captivate…selections, decisions.

  10. Dor
    July 17, 2010 at 6:07 am

    got my computer to “find” my HTC Desire, but when i type “$ su” it says that “su: permission denied”. how could i get permission?
    thanks!

    • July 17, 2010 at 7:51 am

      Hi Dor, did you enter your host machine root password when su prompts you?

      • Chanthan
        December 27, 2010 at 10:27 am

        Dear Black God,

        How can i enter host name machine root password? It don’t prompt me.

        Thanks

        • acid rain
          October 19, 2011 at 3:03 am

          # su root

          that will give you root on a android device. The device itself must alraedy be patched/rooted.

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