[Atrix 4G General] Swiftks:
So what you want to do is this... hopefully this will work for you.

1) Make sure you have the Motorola Drivers installed for your pc setup (i.e. x32 bit or x64 bit)

2) Download and install RSD Lite 5.31 (links in my N00B Guide - http://xdaforums.com/showthread.php?t=1154600)

3) Go here: http://xdaforums.com/showthread.php?t=1136261

4) Download the Unlocker SBF for AT&T users under UNLOCK in the OP (will be labeled pudding.rar)

5) Extract .sbf file to your C:\

6) Put phone in RSD Mode by powering off and upon powering back on hold the Power Button + Volume Up.... should say entering RSD Protocol Mode

7) Open RSD Lite on your PC and drag the .sbf file onto the file path bar (better than finding it with the "..." button)

8) Connect your phone to your PC with usb cable & select device by clicking/highlighting it in RSD Lite Program.

9) Select "Start"

10) It's a small .sbf file, so it shouldn't take long to flash... hopefully you get no errors here... this is the part where if something wrong is gonna happen, it's usually gonna happen here.

11) after sbf flash & reboot, download fastboot files (also available from the Pudding thread, where you got the sbf file from under ROOT)

12) unzip the fastboot files to a folder that you will not forget or delete... ever

13) Put phone in fastboot mode by powering off, then upon power on, hold power button + volume down. select fastboot by pressing volume up button... should enter fastboot protocol mode

14) Connect phone to PC if still not connected

15) Open a command prompt on your pc from the folder you saved the fastboot files (hold Shift + Right Click... Open Command Prompt from here)

16) Type this in command prompt: "fastboot oem unlock" Should see the same thing as the image at the bottom of the OP in the Pudding thread. Can type it again after the unlock process and it should say that you are unlocked.

17) if phone doesn't reboot after unlock, type this command: fastboot reboot and it should reboot phone then, and you will see unlocked signature at top left of screen.

To Root, I would just suggest that you pick a ROM and apply it... most of the well known ROMs will include Root for you. You will need a CWM Recovery to flash most of these ROMs, so that would be your next step: Go here and install this CWM Recovery via fastboot using the commands in the OP: http://xdaforums.com/showthread.php?t=1204500 Make sure to download the version on the left (non-zip version) for fastboot install.

After you have CWM installed you can flash a custom ROM. You can also flash most ROMs with fastboot as well, just check and see if the OPs of the ROM you want to flash has fastboot install instructions.

If you want to attempt Root first before installing CWM Recovery, you can try the 2nd post in this thread which uses fastboot & adb: http://xdaforums.com/showthread.php?t=1138204 The sbf flash in the OP of this thread, which is supposed to include unlock bootloader & Root has been giving some people problems that have stock 2.3.4, that's why I gave you the old school way / directions above. But if you want to try it and ignore all the above directions, I guess you could just try that 600 mb sbf flash for 2.3.4.

Let me know if it works, or you need further explanation / help.... check my N00B guide too:

http://xdaforums.com/showthread.php?t=1154600