i have not used suse, but i believe it uses svsv-init startup scripts (instructions followed by "ok" during bootup)
if one of those messages is about starting the ethernet card, then you will need to find the location of the rc1.d -- rc6.d folders (normally in /etc/ or /etc/rc.d)
in rc3.d or rc5.d, find a script that is starting up the ethernet device and take out execution rights by doing su, then chmod -x whateverthescript
|