If you can't return your HR10-250 (ie: in Canada like me), try going back to the original firmware 3.1.4. I believe I had a similar problem happen to me with my 4 port switch. 6.3a worked fine for me for 2 weeks then suddenly crashed and never recovered. When I tried a reboot, it got to the download screen and stayed at 0% for a day (until I unplugged it). I went back to 3.1.4 and everything is good.