Try adding the command to the end of /etc/init.d/boot.local, then reboot to see if it works. Bool.local is one place to add commands you want to run on bootup.
Note: if you don't have a boot disk of some kind, make one before you try this. The boot.local file contains commands you want to run on boot. But, they run before your system goes to the first runlevel. If boot fails, you will need an alternate means to boot and remove the offending command from boot.local.