Get RSD Lite 6.14 (recommended version) for Windows only.
Get the stock firmware file, make sure you pick the latest ICS firmware file here (7.7.1Q-144_MB886_MR1-22_SIGNED_CFC.xml.zip) for AT&T.
After successfully downloaded, extract the zip file. And edit the 7.7.1Q-144_MB886_MR1-22_SIGNED_CFC.xml file using notepad, and then remove 2 lines with getvar.step operation=”getvar” var=”max-download-size”
Open RSD Lite, open the XML file that you have edited before.
Turn off your phone, and then enter the Boot Mode Selection Menu by press and hold the following keys together (Volume Up+Volume Down+Power). Using vol down, scroll to AP Fastboot menu, and then vol up to select it.
Connect Atrix HD to PC via USB, your phone will be recognized by RSD Lite as MB886.
Now it’s time to hit the Start button, and please wait for about 10-25 minutes.
Once the flash process done, your device will reboot. Your Motorola Atrix HD (MB886) should restore to stock and unroot now.
I disconnected the cable, and now I receive the following message:
RSDLite: Failed flashing process. 1/23 flash partion \\gpt_main0.bin – Phone returned FAIL.
ATRIX HD: downgraded security version
update gpt_main version failed
preflash validation failed for GPT.
Each time that I turn on the equipment, I need to go to Fastboot menu and select normal boot.
Can you help me?