This update brings Gingerbread 2.3.4 to Atrix 4G owners through Motorola's website. The update brings all of the awesome features of Gingerbread to your device such as improved web browsing, HD Video Playback, and other miscellaneous improvements. The biggest improvement to the device is the ability to sideload apps, thanks to AT&T's new policy to allow all devices to sideload.
The update comes in at 161 MBs. I highly recommend downloading this update thanks to all of the new features including the ability to sideload apps. It was about time, thanks Motorola and AT&T.
source: Unwired View