Which version of the WebUpdater did you download and use? (There are 2 Windows versions and the Mac Beta on the download page). As far as the firmware is concerned, evidently Garmin changed the 32MB memory chip of the original eTrex to a higher capacity but kept the model designation the same. The 2.14 firmware is for the original eTrex and version 3.00 or later is for the newer model. You have the newer model so don't go to version 2.14 but you could download version 3.50 and do the test with it. Any possibility that you could borrow a Keyspan USB to serial adapter from someone?