Here is a quick checklist of things you can try.
I still have grub 0.xx how can I use grub2?
If you are using an older Sabayon install like 5.1 or earlier, grub might have been updated as a package, but it still would not be installed to the master boot record. You will have todo that manually if you want to switch over to grub2!
Will install the newer grub to the MBR, from here you need to generate the /boot/grub/grub.cfg
MIND THIS: grub2 does NOT use /boot/grub/menu.lst or /boot/grub/grub.conf anymore!!
To generate your new cfg file as root issue this command:
grub-mkconfig -o /boot/grub/grub.cfg
I have grub2 but it does not work from my external USB drive!
If you use grub2 from your USB MBR you want to add these flags to the kernel line in /boot/grub/grub.cfg
or even better would be to add them here:
and then regenerate you grub.cfg (grub-mkconfig -o /boot/grub/grub.cfg)
reason this is better is because whenever entropy automatically triggers the grub config rebuild script your direct edit on /boot/grub/grub.cfg will be lost.
I have grub2 and it boots fine , but my bootsplash image is corrupted!
Add this to your kernel boot line:
Hope it helps.