Wow, thanks for the quick reply!
Pretty soon after posting I did install with STICK and it is now working (I was hoping to use the firmware update method, but hey, at least it works). I am having a bit of a problem though, maybe it has to do with the S90 port still being in beta or something? Anyways, I can't access certain sub-menus, whenever I hit, for example "load script from file" or "load grid from file", "user menu edit" or "osd layout editor", the screen does a strange sort of 'refresh' flash but stays on the same menu as before, it doesn't open anything. Evidently, this means I can't define my user menu, use the intervalometer, or change the osd. More help?
Sorry to bother, I'm clearly quite a newbie still. Thanks again.
Oh, and PS: there was a ps.fi2 file, and I'm quite familiar with the firmware update menu – I use it all the time on my G10. That's not the problem, it just simply wasn't showing up...(I meant the playback button when I said "play menu")