emusonacid! legacy

hi,
it has come to light that some external drives work with earlier eos but not 4.70, so im trying to roll back the eos from 4.70 to 4.60 or 4.10 on my e6400ultra but cant figure out how to do it. i cant find anywhere
internally you can remove the eos from its flash memeory, & ive
tried inserting floppy's at start up, if i enter flash prep it just
hangs on boot up screen searching for os. & if i just enter a 4.10
eos floppy it thinks the disk is empty. ive searched for a few
hours last night on here & the emu website & can find no
help or mention at all of this procedure. can anyone please help in
any way? thanks