MacOS overrules yaboot on double harddisk G4

[Georg Koss <g.koss@eunet.at>]

Hello all!
Please help! 
I have problem with booting debian on two HD G4. After installing Debian with a "mkofboot ybin-0.26 yaboot 0.8 setup" of my debian-HD with rebooting to Debian immediatly works fine.
But when I boot in MacOS on hda9 I loose the debian- button from the OF-Menue afterwards.

My fstab looks like
hda9        HFS  (Mac)
hdb9      bootstrap
hdb10       swap
hdb11         /
hdb12       /home
hdb13       /var
hdb14      HFS (Mac)

After unpacking the ybin-0.26 archive I did
cd ybin-0.26
cat ybin > /usr/sbin/ybin
cp ofpath /usr/sbin

mkofboot -b /dev/hdb9 -i ./yaboot -m ./ofboot --root /dev/hdb11 \
    --partition 11 --device `ofpath /dev/hdb`

BTW, on hda9 (Mac-HD with 10GB) runs Norton Antivirus for Mac. It is allowed to scan Desktop and Mac-Systemfolder. Can that be a problem for the bootstrap?

TIA
-- 
Greetings

Georg Koss; g.koss@eunet.at