I agree, does sound like a power glitch of some sort. I understand Windows does a hack job reformatting SD cards, writing over some delicate table of some sort but I can't say I've ever run into problems reformatting them with windows, myself.
I had what one would call a bed micro sd card.If one rebooted the Roku the card would never let the Roku finish booting up. Take in the card out allowed the Roku to boot and work properly. To fix I just reformatted in the pc and reinserted it back into the Roku. No clue as to what went wrong. just know the fix.
Roku 2xs (3100x), Roku Express (3900x) ,Roku Ultra (4660RW) .FIOS Quantum modem router, Verizon FIOS 100/100, LG HDTV 42LH90, Pioneer VSX-920 Audio/Video Multi Channel Receiver
I own 3 roku4's, two of which I updated over a year ago with 16GB sdcards. When inserted, the roku's formatted the cards and they've been running fine for this last year. But this last week, a few days after being updated with os9.2 build4131-29 both units started rebooting over and over, until I removed the sdcards. After doing so, they booted up just fine. The 3rd unit that I never upgraded ran without any problems.
Has anyone else seen any problems like this? I'd like to test these sdcards out with my regular computers, but I'm unable to do so right now as my house is being remodeled.