I too have a Sandisk 8GB microSDHC(SDSDQR-8192-A11M) and I too used it with a Kingston mini adapter(it came with a 4GB Mobility kit MBLY/4GBKR) and it didn't work. Both the microsdhc and the Kingston kit are rated class 4. I am using build 2.2007.51-3, which as of this time, I think, is the latest OS2008. When I take the card out of the adapter and use it on other devices, including XP via a usb adapter, it works fine. When I use the N810 via a USB cable to my PC, windows can't see it. Also, I've used my 8GB with other mini adapters on other devices and there are no problems. After doing some searching, Nokia seeems to have problems with Sandisk 8GB microsdhc in other products too, including cell phones. I think this is a Nokia kernel problem, but I have no idea why the previous post with the same sandisk card and Kinston adapter works. fredz, could you tell me what OS version you are using? BTW I also tried formatting the card with Windows XP as well, and it made no difference.

Also, to muddy the water even further, there were several similar OS800 bugs, albeit with N800:

#2073
https://bugs.maemo.org/show_bug.cgi?id=2073

#1204
https://bugs.maemo.org/show_bug.cgi?id=1204