How to stop update-grub from scanning all drives?

Every time update-grub is run all hard drives are scanned. Each drives that is in standby state will spin up to go idle. This is a waste of energy. We use update-grub version 1.98: # update-grub -v grub-mkconfig (GRUB) 1.98+20100804-14+squeeze1 *Regression* 1. There is a GRUB_DISABLE_OS_PROBER=true option in the /etc/default/grub file. But that seems to only work from version 2 and up. At least it doesn't stop scanning all drives in our version 1.98. 2. There is a /etc/grub.d/20_linux_xen script that might be run as a part of update-grub. After removing execute rights for all users with chmod a-x /etc/grub.d/20_linux_xen all drives do still spin up. How to stop update-grub from scanning each and every hard drive?