Problems with grub and partition

[volker67]

Hi,

i tried bhyve and vm-bhyve and want to migrate some XEN VMs for testing and validation.
These are some HVM, PVM and PVH VMs
i tried to use grub as loader for pygrub in XEN.
The Problem is, that when i start the VM, the menu.lst or the grub.cfg could not be found an i ended in grub>
these is the conf file

cpu=1
memory=2048M
network0_type="virtio-net"
network0_switch="bond0"
disk0_type="virtio-blk"
disk0_name="disk.img"
disk1_type="virtio-blk"
disk1_name="swap.img"
disk2_type="virtio-blk"
disk2_name="var.img"
uuid="45393ce6-b28a-11ed-8c71-00145ee8edf5"
network0_mac="00:16:3E:8A:39:AC"
loader="grub"

when i add the following it will work.

grub_run_partition="0"
grub_run0="set root=(hd0)"
grub_run1="linux /boot/vmlinuz-5.4.0-139-generic root=UUID=49424437-5076-48e1-932a-0287d149c680 ro quiet splash $vt_handoff net.ifnames=0""
grub_run2="initrd /boot/initrd.img-5.4.0-139-generic"
grub_run3="boot"

the "Disks" for the VM are not partitioned, this are raw, ext4 formatted Image Files, so i don't need (hd0,1) as grub root
what i need is only (hd0) !!!
But booting without the lines - and type set in grub>

WEEKDAY=
YEAR=
color_highlight=black/white
color_normal=white/black
feature_200_final=y
feature_all_video_module=y
feature_chainloader_bpb=y
feature_default_font_path=y
feature_menuentry_id=y
feature_menuentry_options=y
feature_ntldr=y
feature_platform_search_hint=y
grub_cfg=grub.cfg
grub_cpu=x86_64
grub_platform=emu
lang=
locale_dir=
net_default_server=
pager=
prefix=(hd0,1)/boot/grub
pxe_default_server=
root=hd0,1
secondary_locale_dir=
grub>

so how to change root= or prefix= from hd0,1 to hd0 ??

regards