Update:

Hmmm.. interesting.

The GUIDE button on the ARQ-100 remote now brings up the EPG, which is the first time that's worked since I've owned the ARQ-100 and BuzzTV xpl300 (over a year), which is great!

Unfortunately, I can't back out of the EPG using the Back button on the ARQ-100 now , or using any other buttons on it for that matter, just like the issues with other Menu/Screens previously reported in this thread. Prior to this latest ROM update, in order to get the GUIDE to appear using the ARQ-100 RCU, I had to press the lil' sprocket/gear button in the lower left corner of the remote. After the update, pressing that button brings up the Settings Menu, which is great and seems logical, as one would expect, but once again, I'm unable to back out of that menu either using the Back button on the ARQ-100 RCU, and have to use the original (crappy) RCU that shipped with the xpl3000 stb.

This is both exciting and disappointing at the same time! LoL

Edit:
I tried pulling both batteries from the ARQ-100, waiting a few mins, and while waiting, I used the original xpl3000 RCU to navigate menus, access the Guide, etc., exited to full screen view mode, and then put the batteries back into the ARQ-100 RCU, pressed the GUIDE button, which brought up the EPG again (yay!), waited a few seconds, them pressed the Back button and this time it allowed me to exit the EPG. Maybe the battery removal caused the equivalent of a mini re calibration of sorts...dunno.

I'm not sure what's causing this intermittent bizarre behavior, but maybe if manually rebooting the stb after the automatic reboot has already happened, and then removing the batteries in the ARQ-100 RCU is the trick to keep the RCU working, I'll post an update to that effect later. It seems to be working for now, tho, and hopefully it will continue to do so.