Atrix was the first device by Motorola to come out with a dual core processor. The only problem with this device was that it came out with Android 2.2 Froyo coupled with a locked bootloader. There is good news for all the Atrix users, Motorola will be rolling out a Gingerbread update soon which will also include unlocked bootloader. This gingerbread update was leaked by the guys at Xda developers. Also the bootloader was unlocked. If you have the Atrix and want to unlock the bootloader then you can follow this simple guide. This works on both Gingerbread and Froyo.

Warning:

• This procedure will VOID your WARRANTY
• You will be able to flash custom ROMs once you unlock the bootloader
• Backup your data because you will be losing all your data while performing this procedure
• Read the whole guide before doing the procedure

Downloads:

For devices running Android 2.2 (Froyo):

• Download Unlock SBF file from here
• Download RSD Lite 5.3.1 from here
• Download fastboot packages from here

For devices running Android 2.3 (Gingerbread):

• Download fastboot packages from here

Procedure:

For devices on Froyo:

• Switch off your Motorola Atrix
• Take out the microSD card and SIM card from the device
• Switch on the phone and press volume up button until you a screen which shows, "Starting RSD Protocol Support"
• Run the RSD Lite which you just downloaded on the computer
• Unzip the SBF file you had downloaded to a folder which you can easily access
• On RSD lite click on "…" just beside Filename
• Select the SBF file which you had unzipped
• Connect the Atrix to your computer using the Micro USB chord
• RSD Lite will instantly recognize your device and show you "connected" and "Model: NS Flash Olympus"� beside it
• Click on the start button
• The phone will reboot now. It will take some time to reboot
• Unzip the fastboot� package you downloaded to a folder which you can easily access
• Open cmd prompt on your windows PC (Go to run and type "cmd" and hit enter in windows 7 type "cmd" in search area and hit enter)
• Travel to the fastboot folder from cmd prompt (for example you can give the command : cd C:usersadminDesktopfastboot-package)
• Switch off your device
• Press the power button and volume down button together until you see "Fastboot" on your screen
• Now press volume up button
• When you see "Starting Fastboot Protocol Support" on the screen connect your device to the computer using the microUSB cable
• In cmd prompt type : "fastboot oem unlock" �(without "")
• Now you will receive the device ID as soon as you press enter
• Now in cmd prompt give the command "fastboot oem unlock <device ID>" (do not include <> and enter your device ID)
• Give the command "fastboot reboot" (without "")
• Your device will now reboot with an unlocked bootloader
• Done!� You have successfully unlocked the bootloader of your Motorola Atrix

For Devices on Gingerbread:

• Unzip the fastboot� package you downloaded to a folder which you can easily access
• Open cmd prompt on your windows PC (Go to run and type "cmd" and hit enter in windows 7 type "cmd" in search area and hit enter)
• Travel to the fastboot folder from cmd prompt (for example you can give the command : cd C:usersadminDesktopfastboot-package)
• Switch off your device
• Press the power button and volume down button together until you see "Fastboot" on your screen
• Now press volume up button
• When you see "Starting Fastboot Protocol Support" on the screen connect your device to the computer using the microUSB cable
• In cmd prompt type : "fastboot oem unlock" �(without "")
• Now you will receive the device ID as soon as you press enter
• Now in cmd prompt give the command "fastboot oem unlock <device ID>" (do not include <> and enter your device ID)
• Give the command "fastboot reboot" (without "")
• Your device will now reboot with an unlocked bootloader
• Done!� You have successfully unlocked the bootloader of your Motorola Atrix

Now you will be able to flash custom ROMs on your device. So let the flashing begin!

Source: XDA Developers