I have a vboot installation on a windows 7 primary partition that worked perfectly until I instlled a native ubuntu on a new partition on same disk.
Now the ubuntu bootloader loads at first and when I choose the Windows 7 bootloader to load vboot, I got the "file not found" error with something relating to VCookie missing.
All my drives are pointed with UUIDs and I'm not able to access the VHD boot anymore.
So what's missing ?
Is there a way to plug the modified grub from vmlite into my fresh native unbuntu's ?
Should I lter my grub config ?
Here is my vboot's grub config section:

you can't use vhd command with other GRUB build. You can place the kernel file and initrd on your real hard disk, so you don't have to use vhd commmand.

read this doc:
www.vmlite.com/appliances/ubuntu-1104-readme.html

section 5.2 for more info.

5.2 Configure Legacy GRUB
For GRUB 0.97 and similar, you can add an entry to your GRUB config file, /boot/grub/menu.lst, using any text editor, and insert an entry like the following:

title VBoot - Ubuntu VHD Boot
kernel /boot/ubuntu-1104/vmlinuz-2.6.38-7-generic root=/dev/sda1 vloop=/boot/ubuntu-1104/ubuntu-1104-beta1-i386.vhd vlooppart=p1 quiet splash
initrd /boot/ubuntu-1104/initrd.img-2.6.38-7-generic
quiet


Another simple way is to chain load to VBoot GRUB2.

2.3 Chainloading from other boot loaders
It sIt should be very easy to chainload from other boot loaders.

Chainloading from GRUB2:

menuentry "VBOOT" {
set root='(hd0,1)'
linux16 /vbootldr
}

Thanks for the quick reply.
I had the same problem with both methods.
But the reason was elsewhere : I tried to run the vhd with VMLite and it couldn't open because of an invalid header (error code VERR_VD_VHD_INVALID_HEADER).
I searched for a solution on the net but with no response.
I simply mounted the vhd in Windows 7 and unmounted it (through the disk management tools).
Seems like that operation recreated the header and the VHD could boot again.

Hope it will help.