It would also be interesting to compare whether or not people "fixed" the glitch themselves with RBRs, as opposed to those who weren't home at the time and had the DVRs sitting in the unresponsive mode until DirecTV pushed the reboot. I wasn't home, so ours depended on the pushed reboot, and was in the scan screen when we got home. Different people were also on different NRs, maybe some were recording and some not, there could be many variables.
It's curious that some people have been able to reboot their external drives and others can't. Perhaps the "transmission glitch" affected different brands of drives in different ways.
With external drives being an "unsupported" feature, I doubt that you'll get a solution from DirecTV. At some point, absent of any other suggestions, you may have to give up on maintaining the existing recordings, and try wiping the drive like I did. For me, it was just an issue of spending the time to do it. Since that drive had only been in operation for 10 days, it wasn't like there was a ton of stuff on there (especially considering that it's not our only DVR, and we don't use these DVRs for locals any more). I understand it can be painful with a 2TB drive that has been acquiring programming for a long time.
So far have no ideas other than continuing to attempt reboots and hope one eventually works.