Updating Motorola Xoom 3G (CDMA–Verizon) MZ600 Stingray to ICS

First of all, I would like to clarify that this is not my work, i have collected and followed the process to update my Verizon Motorola Xoom 3G to ICS using the ICS update released by Verizon for the Verizon Motorola Xoom 4G LTE.

Please proceed with caution and please do not blame me if something goes wrong . Remind you it will erase everything on your Xoom, so backup before you proceed. This is for advanced users only. DO NOT ASK FOR ANY HELP OR SUPPORT PLEASE.
This guide is only for those who has not upgraded their 3G Xoom to a 4G LTE version

Things you need, before you proceed.
01. An OTG cable
02. USB pen drive (or SDCard might work, not sure though)
03. ROM for 4G LTE Xoom (You can download the ROM from http://download.peteralfonso.com/stingray)
04. Latest drivers for Motorola Xoom

Download the following:
A. Software Image HLK75D Download Link

B. OTA Updates 01. HLK75F from HLK75D and 02. HLK75H from HLK75F


N.B: You can download these two OTA updates and manually update your Xoom 3G or you can use OTA to update. But YOU MUST have to update your Xoom 3G to HLK75H, or you will not get your baseband back.
You now have to use adb and fastboot tool to change your firmware from Xoom 3G firmware to Xoom 4G firmware.
You can download the lightweight fastboot and ADB files from here.

STEP 1: Updating 3G Xoom (MZ600 – Stingray) to 4G LTE Xoom Honeycomb ROM
Extract HLK75D into the Fastboot folder
Connect your device to your pc, Make sure your have all the latest Motorola Xoom Drivers are installed, USB Debugging is on in your Xoom settings .
01. open command prompt and type “adb devices” . it should show something similar, if it doesnt show anything, then something is wrong, either driver is missing or USB debugging is not enabled.
C:\Fastboot>adb devices
List of devices attached
161c10c9439fb617        device
02. on the command prompt type “adb reboot-bootloader”
C:\Fastboot>adb reboot-bootloader
It will come into the fastboot mode where we can push the firmware onto the device. Remind you it will erase everything on your Xoom, so backup before you proceed.
Make sure your bootloader is unlocked before you proceed furthur. (to unlock bootloader “fastboot oem unlock” and if it is unlocked already please proceed)
02. on the command prompt Type “fastboot flash system system.img”
C:\Fastboot>fastboot flash system system.img
03. on the command prompt Type “fastboot flash boot boot.img”
C:\Fastboot>fastboot flash boot boot.img
04. on the command prompt Type “fastboot flash recovery recovery.img”
C:\Fastboot>fastboot flash recovery recovery.img
05. on the command prompt Type “fastboot flash userdata userdata.img”
C:\Fastboot>fastboot flash userdata userdata.img
06. on the command prompt type “fastboot erase cache”
C:\Fastboot>fastboot erase cache
07. on the command prompt type “fastboot erase userdata”
C:\Fastboot>fastboot erase userdata
08. Assuming your device is already OEM unlocked, now type “fastboot reboot”
C:\Fastboot>fastboot reboot
Now the device will restart, and you will have Honeycomb on your device, but you will notice that the baseband is missing.
Now update the device Over the Air to HLK75F and then to HLK75H or manually from the download OTA files.
After updating the ROM to HLK75H, the baseband for 3G CDMA will return, but i cant promise it will work, as i dont use CDMA.
When you have finished upto this point you are now ready to update your 3G Xoom Honeycomb (using 4G LTE HC ROM) to ICS
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STEP 2: Update to ICS
Download the OTA update for ICS “2a903016f227.signed-trygon-IMM76L-from-HLK75H.2a903016.zip”
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Update Instructions from Droid-Life.com
Instructions:

*Instructions require a USB host cable (like this) and USB drive/stick.
* You will also need to be on Android build HLK75H

1.  Download the file from above and drop it on a USB stick or SD card that can be put in a USB Stick.
2.  Turn your XOOM off.
3.  When you power it back on, tap Volume Down at the red M logo until it says:

–> Android Recovery

4.  Tap Volume Up to enter recovery mode.
5.  At the green Android logo, press Power and Volume Up.
6.  Plug in your USB drive to a USB host cable and then into your XOOM.
7.  Scroll down to “apply update from USB drive” and select it with Power.
8.  Scroll down to the .zip update file from above and use Power to select it.
9.  Your XOOM will now update.
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[Most of these processes has been copied from http://www.droid-life.com/2012/06/04/download-motorola-xoom-4g-android-4-0-4-imm76l-update/]