used Ubuntu live CD to get into tthe system:
--mounted sdb3 whre my /root lies
--edited /etc/yaboot.conf and made it look like this:
-----------------
boot=/dev/sdb2
device=/ht@0,f2000000/pci@5/k2-sata-root@c/k2-sata@1/disk@0:
partition=3
root=/dev/sdb3
timeout=100
install=/usr/lib/yaboot/yaboot
magicboot=/usr/lib/yaboot/ofboot
ofboot=/ht@0,f2000000/pci@5/k2-sata-root@c/k2-sata@1/disk@0:2
enablecdboot
enableofboot
macosx=/dev/sda9
default=Linux
image=/boot/vmlinux
label=Linux
read-only
initrd=/boot/initrd.img
image=/boot/vmlinux.old
label=old
read-only
initrd=/boot/initrd.img.old
------------------
--mounted /proc
--ran ybin -v (seems that everything worked)
--restarted and chose linux from the yaboot menu
--got put pack into the "option" menu