I don't specifically recall folks trying and failing to do the update from Win98, but that may simply be because nobody tried it. If I were the one trying it, I'd focus on the RS-232 approach. USB under Win98 was always a bit of an adventure, and it's very possible that this is why Outlaw recommended WinME or higher for the 990 firmware update. Outlaw support might be able to confirm one way or another.