Why i answer this threat even if it's very old? The answer is pretty easy, because so many other threat refer to it.
hwinfo --framebuffer doesn't show the native resolution of your display, then disable vesa, to do so remove vga= options in:
sudo nano /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT= and remove
vga= if you find it.
If you have remove the option don't forget to generate a new grub.cfg:
If you don't know you did it well, then just reboot and open a terminal:
grep vga /proc/cmdline
grep -ir vga /etc/modprobe.d/
If grep doesn't show anything, then you removed the vga= option.
Now install uvesafb:
sudo apt-get install v86d
Make sure the uvesafb module is included into your initrd. Add it to the end of /etc/initramfs-tools/modules:
sudo sh -c "echo uvesafb >> /etc/initramfs-tools/modules"
To see what modes are available:
sudo modprobe uvesafb
Now configure uvesafb mode_option=YOURxResoultion-BitColorMode e.g. 1280x1024-32:
sudo sh -c "echo options uvesafb mode_option=1280x1024-32 scroll=ywrap > /etc/modprobe.d/uvesafb.conf"
Don't forget to rebuild your initrd:
sudo update-initramfs -k all -u
Now you can reboot!
See this for more details.
It is for debian, but it also works for ubuntu.
I hope it helped you and it should be more generic than using grub2.