grub2, update-grub, /etc/grub.d

[Hugh Lawson <hlawson@triad.rr.com>]

grub2 (provided by package grub-pc)

Suppose you want to add something like "vga=791" to the linux line of
one of the stanzas auto-configured by update-grub.

What is the debian way to do this? 

I know how to edit the grub.cfg file to do this, but won't this file be
replaced by the next 'update-grub'?  The scripts in /etc/grub.d are
over my head.

I also have successfully edited /etc/grub.d/40_custom to produce
home-made custom stanzas for /boot/grub/grub.cfg.

Thanks,

Hugh