Can it be done?
Trying to upgrade on my ol' 2501's to 12.3 turned into such a disaster; I had TFTP checksum errors ad nauseum, and many other probs.
A forum member told me the TFTP client in IOS (or bootstrap? it can't be in IOS if it's copying the images and erasing the Flash where the IOS actually resides, can it?) is actually rather weak; and that I should use FTP instead.
Well, I've got 3C Daemon FTP server installed on my laptop, but what I can't find is info on how you actually get the transfer going, using FTP.