Problem (eventually) solved - I was unable to write sectors to the SD card while the adaptor was plugged into a USB hub, but the minute I plugged it directly into a USB port, it worked first time. D'oh!
Hi Maël, Much like tripley, I'm trying to use HxD to write raw data to a 2GB MicroSD card under Windows 7 - specifically, I'm trying to write ~8K to the card starting from sector #3854318. I'm first unmounting the logical drive (h:) [as you suggested in the other thread], but am still getting "Acces...