Hi, with the version of the Boot floppies etc available about a week ago I got the 'Arch not supported' message myself while trying to install on a Rev B iMac. I ended up getting Debian on my machine by lnstalling a small partiton of Yellowdoglinux, unpacking base2_2.tgz etc ( The old way ). If you want anyone to try out newer boot floppies on a 1st Generation iMac I'd be pleased to help Cheers Derek