am running Trisquel 5.5 on two MacBook2,1 (late 2007) machines. One is set up
as dual boot besides Snow Leopard (my mums machine) and mine as single boot.
most things work out of the box even the wifi, but not so the camera. i dont
care about that though. there are lots of informations for other macbook
(pro) versions on the ubuntu forums, they call it mactel i believe... most
things i found there also work for Trisquel.
well i just remember that i had to add something to the grub.cfg file to make
the graphic card work. (Intel 945GM Chipset, GMA 950) adding
fakebios and fix_video before the kernel is loaded and kernel options
video=efifb noefi did it for me.
besides that i'd think lembas' idea using a live-cd and try sounds good