A great guide to ADB/Fastboot, custom recovery and root
Below is a great guide to rooting, from several sources, (mostly taken from pingvinen's "An Idiot's Guide to Flashing the Xoom" and a guide by publicanimal. and I hope it helps. You can find the links to all of the files referenced below in the Xoom Heaven thread (thanks diablo2224!)
"What you need to do can be encompassed in these following short steps (will be detailed later on) in the following order. Each step is required before you can proceed to the next one. However, make sure that you are very very careful and dont try to take any shortcuts. That may soft-brick your device, and you may have a difficult time to explain that to your wife ... You have been warned!
I strongly recommend you to read the entire guide before trying this. In fact, read it twice to ensure that you have understood everything. If there is wierd stuff that you dont understand, dont hesitate to ask. The reason for me writing this down is that I like to document what I have learned. This is to me an excellent way to ensure that I will remember what I just did. Another reason was that I could not find a single thread that encompassed all steps required. There are many different threads, but noone (that I could find) that really guides you from start to goal. So enjoy and good luck!
I would like to thank LandMaster and cam30era for helping out with advice during my initial trail-and-error session. I soft-bricked my device once and had big problems to get by point 4.3 (avoid overwriting of CWM), but with their encouragement I finally succeeded.
Overview of the 6 required steps
1. Install Motorola USB drivers for your computers (for USB connectivity) 2. Install Java SDK and Android SDK tools (for adb and fastboot commands) 3. Unlock the device for flashing (allowing replacement of recovery and boot images) 4. Install a modified recovery image (ClockWorkMod recovery for Android) 5. Root the device (Allow r/w access to the device filesystem) 6. Flash a kernel that supports overclocking etc.
Steps 1, 2, 4, 5 and 6 require that you download install, image and zip files needed for the flashing.
All this was performed on a Windows PC. Windows 7, Mac and Linux users will probably have to do some steps differently.
1.0 Install the latest Motorola USB drivers
The installation file can be found here
http://www.motorola.com/Support/US-E...arging-Drivers
1.1 Install the drivers and ensure that your Xoom is recognized by the computer
2.0 Installation of development software
Java SDK 6 and Android SDK need to be installed. You can find the installation kits here.
http://www.oracle.com/technetwork/ja...ad-400750.html http://developer.android.com/sdk/index.html
2.1 Install them as any other software, making an Android SDK folder on C/.
2.2 Make sure that all the files you need are in the
Platform Tools folder (fastboot, Tiamat R4c recovery image file, etc. Copy any files in the Tools folder to the Platform Tools folder if necessary. Note: If the Android SDK complains that the Java Dev Kit can't be found, just press Back and then Next again. Wierd, but that seems to do the trick ... go figure.
(
Warning: Never put any zip files in your Platform Tools folder. Flashing zip files through fastboot will cause very serious problems.

Zip files must be flashed from the external micro SD card through CWM recovery on the Xoom...we'll get to that later.)
2.3 Test that ADB and FASTBOOT works. You should open a command window by right clicking in your Platform Tools folder where all of your files are, plug in your Xoom to your computer with your Motorola cable (it may not work with a generic cable) and write 'adb devices'. Your Xoom should now be listed. Did your device not show up? Make sure that you have USB debugging enabled in Settings/Applications/Development on your Xoom.
3.
Unlocking the device for flashing
This step will effectively erase the internal storage, including all your apps and settings. Use whatever backup you want to secure important data before you start.
3.1 Power up and start the Xoom.
3.2 Ensure that your device is fully recognized by the computer. A good sign is that the 'Portable device' dialog is activated on Windows when your Xoom has booted. The Xoom should also be seen in 'Computer'. If not, go back to step 2 and double check your USB drivers.
3.3 Use the command '
adb reboot bootloader' to go into Flash mode.
3.4 Use the command '
fastboot oem unlock'. This will trigger a dialog on your Xoom. Follow the instructions on the screen to complete the unlocking. I repeat, this *will* do a factory reset and all data will be lost!
3.5 Once unlocked, the Xoom will restart and work as normal. Don't bother to do any setup at this time, just make sure that USB debbuging is checked in settings, and now go on to step 4
4.
Install recovery image (CWM)
If you haven't done it already, download the recovery image file and save it to your computer in the Platform Tools folder.
4.1 Boot into flash mode with '
adb reboot bootloader.'
4.2 Install your downloaded recovery image: '
fastboot flash recovery recovery-Tiamat-R4c-100611-1150-cwm.img' or
whatever is the exact name of the recovery img file you are flashing.
4.3 Restart the device with '
fastboot reboot'. Timing is essential here, so be alert when the device restarts, or you will have to redo section 4.
4.4
Enter CWM recovery with the following procedure.
4.5 Once the Motorola logotype is shown, start counting to 3. At 3, press the Volume Down button. This should result in the text 'Android Recovery' in the top left corner. If it does not work, experiment with the timing (see below).
4.6 When 'Android Recovery' is shown press the Volume Up button. This should invoke the CWM recovery menu. If that works, then congratulations for getting this far!
Here is a potential pitfall. If you are unable to enter CWM *before* the device boots into Honeycomb, then the newly installed recovery image will be overwritten by the system default recovery. Just repeat steps 4.1 through 4.6 if that happens.
5.
Rooting the Xoom
The Universal Xoom Root zip file from solarnz is located here:
http://forum.xda-developers.com/showthread.php?t=1242241
5.1 You need to transfer the Universal Xoom Root zip file to a working external micro SD card. You can do this on a computer or cell phone, but the Universal Xoom Root zip file must be located in the root directory of the micro SD card.
5.2 Insert the now prepared SD card in the Xoom.
5.3 Boot into recovery (as described in 4.3). Navigate using the volume buttons and press the power button to select the active option.
5.4 Select 'Install ZIP from sd card.'
5.5 Select 'Choose ZIP.'
5.6 Navigate to the ROOT zip file with the Volume buttons and select it with the Power button. Confirm that you want to install it.
5.7 Everything should indicate success, so back out to the main CWM menu and reboot the device.
5.8 From Android Market, install any app requiring root and start it. If the rooting was successful, then the app should request superuser permission and you should be able to grant it without any problems.
6. Flashing a new rom or kernel...(e.g. Tiamat Hammerhead Rom and/orTachi Kernel). Look in the
Xoom Heaven thread or in the Development section of this form for all of these files.
6.1 This step is identical to 5, but swap out the ROOT zip for the ROM or KERNEL zip. For simplicity, you may want to prepare the micro SD card with both zip files at the same time in step 5.1..."
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This is still one of the best explanations of how to use adb and fastboot to unlock and root the Xoom and install a custom recovery, etc, and doesn't deserve to buries on back pages of this forum. Hopefully, the step-by-step nature of this guide will help those of you that have limited experience with this kind of tinkering.
Oh, and please feel free to correct any errors or omissions. As I said, it came from several sources and needed to somewhat updated.