Success! The N810 recognized a USB flash drive that takes a CF card (MediaGear MGXC-100). It came right up in File Manager. Even lit up the little blue LED.

It doesn't recognize my Simpletech Bonzai SD flash drive, using any number of SD cards, formatted on the PC or in either of my cameras. I'll get another SD flash drive and try it.

Since that is a micro to USB adapter, it might not have the fifth wire to enable host mode. I'd guess that's why the OP used the two connectors described in his first post.

If you intend to solder the host mode sense wire, you'll need some length of cable. His assembly is only 5" long.