21
Jan
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The Optimus G on Japan's Docomo network is an interesting device, as it ships with a mandatory access control system that basically prevents remounting system, reading boot, executing tasks with root privileges, and things of that nature. Thus, the root process for this version of the Optimus G was a tricky one.

A backdoor found by Android hacker giantpune will be used, which allows the bootloader to be unlocked, a modified boot.img to be flashed, and some security features to be disabled – ultimately allowing root access to be achieved.

Now that you have the basic idea down – a couple of noteworthy things:

  • Graphical glitches will occur while in the bootloader. This means you will have to navigate the bootloader "blind."
  • You need to download this package before you get started. (Mirror) (MD5: 70b93a8e8a29bfd2727ae3eb5984af10)
  • If you're using a Windows machine, you'll need to grab the fastboot drivers from here.

Disclaimer: Android Police isn't responsible for any harm to your device - proceed at your own risk.

Got it? OK, let's get started. Follow these instructions exactly!

First things first – extract all the files in the Docomo_OptimusG_Root-v1-AndroidPolice.zip package and open a terminal/command prompt in that location. Execute the following commands.

adb push lk.img /data/local/tmp/lk.img

adb push unlock.sh /data/local/tmp/unlock.sh

adb shell chmod 755 /data/local/tmp/unlock.sh

adb shell touch /sdcard/g_security

Now disable USB Debugging (in Settings > Developer Options), then re-enable it.

adb shell id

At this point, you should get an error about not executing /system/bin/sh – that's a good thing. If you didn't get the error, go back to the beginning and start over.

adb push hotplug /proc/sys/kernel/hotplug

Now toggle Bluetooth once and wait for the phone to display a "garbled" screen (this is the bootloader). If it displays a blank screen, pull the battery, reboot, and run 'adb reboot bootloader'.

fastboot devices

If you see your device, then you're good to continue. If not, you probably need to install the fastboot drivers you downloaded earlier.

fastboot flash boot boot.img

fastboot reboot

adb shell /sbin/rootme.sh

After that, simply head into the Play Store and grab SuperSU. That's it – you're done!

If, for some reason, your phone doesn't reconnect to the mobile network, reboot it several times. If that doesn't help, you'll have to re-flash stock firmware.

Special thanks:

adb backdoor: giantpune
Duct tape guru: jcase
bootloader: The Freegee guys
Testers: Shados and germes81m

Cameron Summerson
Cameron is a self-made geek, Android enthusiast, horror movie fanatic, musician, and cyclist. When he's not pounding keys here at AP, you can find him spending time with his wife and kids, plucking away on the 6-string, spinning on the streets, or watching The Texas Chainsaw Massacre on repeat.

  • Paul_Werner

    I just came here to say that the hacker's name is awesome. Giantpune??? Who comes up with this stuff, lmao

  • kkasa

    Most of smartphones released not only this in Japan is locked.

    RAZER M - can't root

    XPERIA S(NX),XPERIA T(GX) and maybe Xperia Z - can't flash custom roms

    Smart phones such as Sharp and Fujitsu and any Japanese manufacturers - can't root

    Fuck

    • jcase

      Not yet rooted != can't

      • kkasa

        thanks

  • Sebastian

    Wow. What great timing since I'll be working in Japan soon. :)

  • misudoll

    yahoo~~~It's a great job :)

  • Paul

    Wow and I thought the U.S carriers were particularly nasty about locking their devices and security features. Seems NTT Docomo has AT&T/Verizon beat. I just don't understand why they can't make it easier to root but include giant warnings about voiding warranty and such. Let users do it at their own risk. Just like Google does with Nexus's. The Nexus One was easy enough root but if you unlocked the boot loader it'd void the warranty. Let it be the users choice.

  • Robert Poulton

    Is there a thread/forum link for this?
    On the Docomo Galaxy Note 2 we managed to get root working with a similar method although some root apps still cause restarts.
    Wanted to know if Optimus LG users were experiencing any problems with apps like stericson's busybox, root manager, orange backup?

  • http://twitter.com/bangmaroo 김주관

    I was successful according to Rooting provided.

    However, if you put the camera and restart after a few seconds. Is there a solution to this problem?

  • francesco

    I am not able to disable debugging mode. Anybody could help me?

  • fawad

    i have a problem in my cell fone docomo optimus bright l-70c,it shows no network,sim card is inserted also.when i purchased it worked fine.now i i am facing the problem,

    pl help.send me email of the solution.

    fawad_kulachi@yahoo.com.

    Regards

    Fawad

  • Qcgarfield

    Hi! I bought a docomo l01e and try to root like that.

    I done this:

    adb push lk.img /data/local/tmp/lk.img
    adb push unlock.sh /data/local/tmp/unlock.sh

    After each line, i saw some kind of copy action.

    I enter that after:

    adb shell chmod 755 /data/local/tmp/unlock.sh
    adb shell touch /sdcard/g_security

    I see no special action, its look like i type a line with enter and the phone/computer doesnt care!

    After that, to disable usb drbugging, i have to disconnect the data cable, uncheck.

    At this point, does i have, when i uncheck the usb debugging option to reconnect the cable, disconnect again to re activate usb debugging( because i can check/uncheck when data cable is connect )

    After that, i type adb shell id, and its give me many line( but dont look to.have error inside)

    I try to continue with:

    Adb push hotplug, and the phone dont crash, but give me error...

    So i dont want to.brick him.....

    Please help me, that my first time i use adb function.

  • pigo666

    very interesting,Led Lampen the best