[Asus Transformer TF700] waltnich:
Have You Lost Root? - Can't find or reinstall su (su binary) ?

Issue:

Your Transformer or other device is unlocked and rooted, you have a custom recovery like ClockworkMod installed and you flash a rom or an update and when done you find you have partial root or no root at all.

Some apps that have previously been granted superuser permission may load while others, including superuser, super su, busybox, Voodoo, CWM say you don't have root, you are missing the su binary file.

When you run Root Checker it might look something like this link.

SOUND FAMILIAR?

Most likely the flashed ROM or update erased the \system\bin\su and system\xbin\su files and didn't replace them.

Since CWM requires the su binary file to get root access to restore from my nandroid I had to use fastboot to get into recovery.I went to my SDK drectory, sub directory platform-tools where fastboot resides..

If you do not have an SDK directory just download SDK installer from [url]http://developer.android.com/sdk/index.html[/url] to C:\android-sdk\platform-tools

Once the SDK Manager comes up put a check in Tools (this will put a checkmark in the two daughter files) Remove any other checkmarks..Hit the Install Packages bar at the bottom.

This platform-tools folder has fastboot.exe command and is the folder you will work from. You can also copy all the files you want to push into this directory but for now we will concentrate on our issue..

Connect your device to your PC, then turn off your device and boot into fastboot mode on your device.

If you don't know how:

hold down volume down and power button until you see white text on the screen, let go both buttons, use the volume down button to switch the highlight to the USB icon (this is fastboot mode), now hit the volume up button twice.

On your PC open command prompt and navigate to the fastboot directory which is C:\android-sdk\platform-tools

Once you there type the following:

fastboot -i 0x0B05 flash recovery recovery.img (check the specific recovery.img file that you have. It could be recovery-jb.img or recovery.blob etc).

Once the process is done type the following:

fastboot -i 0x0B05 reboot

your device will reboot.and can now boot into recovery.

Turn your device off and re-boot into (clockworkmod) CWM recovery

(hold down volume down and power button until you see white text on the screen, let go both buttons, now hit the volume up button twice.)

You want to hit wipe cache partition. When done hit advanced then wipe dalvik cache then go back.

Now hit backup and restore. Once there hit advanced restore from internal sdcard (where you put your nandroid) Then highlight the most recent date

In Advanced Restore hilight Restore system

Once done you can exit out (go back) to reboot system now

Once device boot up find and open superuser app, then download "root checker" from the market and verify that you have root.

RECAP:

Connect device to PC and boot device into fastboot

On your PC open command prompt and cd to C:\android-sdk\platform-tools

type

fastboot -i 0x0B05 flash recovery recovery-jb.img (.img file exactly as it is in platform-tools) hit enter

when process is done, at the prompt type

fastboot -i 0x0B05 reboot (your device will reboot).

Turn your device off and re-boot into CWM recovery and wipe cache and dalvik cache

go to advanced restore and only Restore system

go back to reboot system now

Once device boot up open superuser app, then "root checker" and verify that you have root.

Enjoy