I have the very same issue regarding bootmenu - not being able to select any bootmenu entry, nor with mouse, nor with keyboard. These are - low cost - usb mouse + usb keyboard, occupying the only 2 onbord usb ports at my MDD's back. At the bootmenu i can only move the pointer up and down with the mouse but if i press a mouse button (cant remember if its lef or right or just any) the pointer will slowly starts to move at the right direction - only, no left - as well (duh i have to move the mouse like mad:) But, even if i can reach an icon with the pointer theres nothing happens when i press any mousebutton with pointer above it. I can only proceed with "Enter" key which results to boot the 1st entry (MorphOS, the default) as no response to any other keyboard press at this stage other than "Enter" (while i can reach the firmware console, or get the bootmenu or boot from cd by pressing "C", so it seems the keyboard is not working properly only at the bootmenu). Therefore i couldnt boot into OSX since i've installed MorphOS, which is painful as i get the awfully loud and annoying bootjingle after every reset.... However at least it boots into MorphOS, even from CD (with a bit luck:).