I've tried reformatting the USB stick and reinstalling the files, and I can't even get the Gekko to boot into E2 anymore. No matter how long I hold down the channel-down button, either it boots into the Optibox firmware, boots into the Optibox firmware but without a display (I verified that it was the Optibox firmware and not E2 by logging in via telnet and checking the directory structure, among other things), or hangs with a green light but no display and no network access.

Totally clueless what's going on here. I've verified that the stick is bootable (or at least Windows claims it is), so I would expect that I could at least get into E2 with a defective video output like the first time, but I can't. I guess my next move is going to be checking whether I can re-flash the new boot loader.