Chris, as you know this problem was first reported to Rogers in November 2010 (almost a year ago). At that time I had two purchased 8300HD in use. Some time in December after the HDD failed in one unit, I contacted Rogers, told them I was taking my purchased units offline until they fixed the issue and they supplied me with two "free" 8642 rentals. I noticed the iHDD on the 8642s were also cycling on and off every few minutes and reported this to Rogers who told me they did not believe there was a problem with that model. The second or third time I called and spoke to a level 2 Supervisor who still didn't acknowledge there was a problem with the 8642, I told them that since the PVRs I'm using are Rogers rentals, I didn't really care if they were damaging them. I haven't bothered calling them since. One good thing about the 8642 is that it uses a SATA HDD which are inexpensive and easy to find, unlike the PATA drive in the 8300.
This HSUD problem is widespread and should certainly be known about by Rogers. I think that because the 8642 is so quiet compared to the 8300 that not as many people notice that it is going on. Everyone was too busy complaining about the 8300 HSUD issue.
My 8642's hard drive has been going crazy since the day I plugged it in . . . Rogers is going to be replacing a lot of hardware in the future!