I guess that fastfilesystem, but I think devices need to be "patched" to support 64bit so you'll probably need the devs:amigaos-rom-update, the file with the configuration of those devices and c:setpatch
I guess that you could also use TD64.
If I remember correctly before OS3.5 Amiga Inc a small update for fastfilesystem and setpatch that was supposed to allow you to use >4GB.
