Comment # 2 on bug 1182957 from Andrei Borzenkov

(In reply to Dr. Werner Fink from comment #0)
> Created attachment 846693 [details]
> output of `grub2-install -vvvv  /dev/nvme0n1`
> 
...
> grub2-install: warning: Embedding is not possible.  GRUB can only be
> installed in this setup by using blocklists.  However, blocklists are
> UNRELIABLE and their use is discouraged..
> grub2-install: error: will not proceed with blocklists.
> 
...
> 
> Model: NVMe Device (nvme)
> Disk /dev/nvme0n1: 128GB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
> Disk Flags: 
> 
> Number  Start   End     Size    File system     Name  Flags
>  1      1049kB  8591MB  8590MB  linux-swap(v1)  swap  swap
>  2      8591MB  19.3GB  10.7GB  ext3            boot  legacy_boot
>  3      19.3GB  128GB   109GB   xfs             root

The error is correct. To install in  "MBR" on GPT disk grub needs bios_boot
partition which is missing. Or you force installation using blocklists on /boot
partition.