The N810 also has troubles with SD card readers. Ultimately an SDHC reader was found that works. I matched it with a short 6 inch cable that keys host mode on the N810. So far every SD card I tried works including an 8GB SDHC. IMHO this may be a safer way to support higher capacity flash. Parts I bought follow:

Targus TGR-SD20 SDHC reader
http://www.walmart.com/catalog/produ...uct_id=9722060

Cable - microUSB to Female USB A. Automaticaly sets the USB to OTG.
http://search.digikey.com/scripts/Dk...name=H11576-ND