GRUB always enters a rescue shell.

[Hao Lee]

Hi,

Thanks to all of you and sorry for the delayed response.
I have addressed this problem. Using `kpartx` instead of `losetup` to
mount partition and I finally make a bootable disk image.
The explanation of this problem together with the solution is here:
http://lists.gnu.org/archive/html/help-grub/2017-07/msg00017.html
Thanks for your help and I hope this will help people who encounter
the same error.

Regards,
Hao Lee