i have ps3 40gig version (modded with 200Gb hdd
and have pleasant time installing linux there (needless to say default ydl linux is slow as hell).
So what i learned:
x)to reboot ps3 to default os hold power button until second beep! at boot time(also works if you want switch to s-video/hdmi output)
x)to install ydl you must type ydl kernel image name there(read install instructions on ydl site) or wait(don't press any keys!!) to autoload it. (second attempt of full format ps3 hdd + 10Gb otheros parting do the trick for me.)