Patch committed.
The last problem is PEBKAC: you compiled upstream with path=/boot/grub and didn't have config file there.

Hi phcoder(Vladimir),

The patch which you gave on 26th March, works partially. We applied the patch NVMe.diff and compiled the grub2-02-beta2. With the latest grub binaries we installed grub on NVMe device

#grub-install --boot-directory=/mnt/sysimage/boot /dev/nvme0n1

After rebooting and booting from NVMe device. It entered into grub prompt

grub>
grub>ls
(hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,mdos1)
grub>

After Manually Setting root, linux and initrd
we were able to boot Linux Fedora from NVMe device.

Thanks & Regards
Vinayak Holikatti

Hi All,

We have developed Legacy OptionROM for NVMe controller device. We are able to boot to all Windows 7 and later OS. But we are facing issue in booting Fedora 20 x86_64 OS. Fedora 20 gets installed successfully on NVMe device. While booting from NVMe device we are observing error as follows and enters grub rescue. boot to Fedora 20 OS from our controller.

"error : no such device: 44d1bf09-4e8a-4f46-aea6-09e364abf5cb.
Entering rescue mode...
grub_rescue>"

The ls command at grub_rescue shows as below
grub_rescue>ls
(hd0)

And set command output as below

grub_rescue>set
prefix = (hd0)/grub2
root = hd0

Earlier we have been seeking help from help-grub mailing list.

We got help from Jordan Uggla <jordan.uggla@gmail.com>. He has some insight on the problem as below

"It looks like the problem is as I expected, grub-install is treating /dev/nvme0n1p1 as a drive (not a partition), and is treating /dev/nvme01 as another drive, with no relation to /dev/nvme01p1.
 
From there, it realizes that you're doing a cross-disk install (though you're actually not) and so configures things for that case (searching for $prefix by UUID), and it also realizes that there is no partition table on /dev/nvme0n1p1 (because said device is a partition) and so expects that it will not need any partition modules at boot to read from it.

You can likely work around this problem therefore by running
"grub-install --modules=part_msdos /dev/nvme0n1", but please try grub 2.02 beta2 anyway (without --modules) and file a bug report if it fails, even if this works, because A: It's an ugly hack that could stop working at any time and B: It would be nice to have this working properly by 2.02 final."

We tried the solution which Jordan Uggla <jordan.uggla@gmail.com> suggested.

We tried to install grub after Linux FC20 Installation by using the below command line

"grub2-install --modules=part_msdos --boot-directory=/mnt/sysimage/boot /dev/nvme0n1"

With above workaround we are able to boot Linux Fedora 20. But Jordan expects this to work withour the workaround for grub 2.02 beta.

With Grub 2.02 beta we are still facing the issue to booting to NVMe device. Booting from NVMe device enters GRUB rescue prompt.