grub configuration for extended video modes

edit the kernel line in /boot/grub/grub.conf and add something like vga=792.

for instance, change this:

kernel /boot/vmlinuz root=/dev/sda1 ro quiet splash

to this:

kernel /boot/vmlinuz root=/dev/sda1 ro vga=792
Table 1. modes
color 640x480 800x600 1024x768 1280x1024

8bit

769

771

773

775

15bit

784

787

790

793

16bit

785

788

791

794

24bit

786

789

792

795