I'm just catching up after the long weekend, but when I did this on a BEFSR41 I just used the suggested MacTFTP and it worked OK. As I recall, the main problem was I had to use Internet Explorer --which I ordinarily never use--to get the admin page to render properly. But this was a while ago, and I think there was some other problem I don't recall the details of now, because something I do have a clear memory of was the Linksys Tech "Support" person on the phone (in the Phillipines) saying about the problem that they didn't really recommend upgrading firmware, rather just use what came originally with the unit (saves him knowing what to do, right?). At one time I was setting up three BEFSR41's each with different original firmware, ended up with the latest f/w on all three, as I recall.