I tried a few things to reset the usb mode, including a trick where you pull the battery for 30 minutes, reinstall the battery plug in the charger and press the swap/home button. it powered up with most of the settings reset to default but no change in the usb problem.
I tried using the usbcontrol utility to no avail.
I tried it on a Windows XP machine using Superstar's instuctions. I had not made any HD changes.
I tried a several different cables and usb ports.
I tried several different SD cards.
I get the same reaction from the computers and the N800, Nothing.
And yet when I try to flash the unit,on the XP machine the usb logo shows up in the top right but the software does not see it.
And still, when I use the OTG adapter it reads my Fuji camera just fine.
I'm perplexed.