UEFI GRUB boot menu disappears after booting into Windows 8

[Joan Jerez]

Hello,

After 6 January of 2013, I started to get problems when I boot into 
Windows 8, and upon restart or shutdown, GRUB disappears and it boots 
directly into Windows.

I tried to remove (moving to another place) EFI applications related to 
Microsoft (after installing Ubuntu, they are named bootmgfw.efi.bkp and 
bootx64.efi.bkp) to ensure that they are not interfere with booting. As 
far I can remember they are in /boot/efi/EFI/Boot and 
/boot/efi/EFI/Microsoft/Boot/, now these folders are populated by GRUB2 
EFI applications.

The problem isn't solved by doing so, so UEFI firmware is not escaping 
GRUB and booting directly using MS bootloader.
Curiously, a long workaround is change booting method from UEFI to 
Legacy, boot to a CD/DVD, or USB, shutdown, and change it again to UEFI, 
and GRUB miraculously appears again.


GRUB2 efi files are dated 3-01-2013 (I installed Kubuntu before, in 
December), and I don't know if it's a regression because it don't 
happened before.
I don't know too where to get a older version of bootx64.efi of GRUB2 to 
test if problem is solved.