The folks at XDA held my hand through the whole process yesterday, and here is the step by step process. The SBF flash hardbrick is only a problem for downgrading, it it safe for installing Pudding.
Origional XDA thread
Incognitum said:**I've been getting PMs for clarification: I didn't do a single mod to my phone before this morning. Stock ATT/Moto Atrix, installed stock ATT/Moto OTA GB update yesterday. Following these steps I am now BLUL and rooted.**
So here are all the steps needed to get a stock, OTA Gingerbread Atrix Unlocked and rooted:
1. Follow Brief Mobile's BL unlock guide here.
Things I found out that you may like to know:
-You will need to complete all steps *even the ones the guide says to skip*.
-When you enter your device unlock code, it is case sensitive; use caps-lock.
-The most recent SBF flash is in the XDA IHOP pudding thread, use this instead of the older file linked to in the Brief Mobile guide.
-When you are done, reboot will take a *long* time; just stay calm.
Edit: After 30 min on the dual core screen with the "unlocked" in the corner I pulled the battery... after reboot everything seems fine.
2. Follow Brief Mobile's guide to root here.
Thanks to brief mobile, and to the xda folks who held my hand through this whole thing the first time
Origional XDA thread