I had the same trouble under linux and windows with 230 and 53.18 firmware. Then I upgrade to the la-*test*-('") ops.(23 i think) and that got the computer to see the challenge. The next problem I ran into was that there is a new challenge key that hasn't been unlocked yet. The challenge starts with 17. There is a discussion in the Camera Discussions thread.
forumer.com/viewtopic.php?t=2502&start=50&postdays=0&postorder=asc&highlight=" target="_blank">http://camerahacks.10.
forumer.com/viewtopic.php?t=2502&start=50&postdays=0&postorder=asc&highlight=