trying to boot openbsd image

[lakus]

Hello,

i try with ipxe(latest from git) to boot an openbsd6.4 image, from a Debian machine with tftpd and http server, the image, which usually i put on a usb pen drive and it boots successfull, but if i try the same image to boot from ipxe, openbsd stops with a kernel panic cause not found of the root device which is usally /dev/wd*.

i tried many different configuration but none of them was able to successfull boot openbsd.
in my real_boot_script.txt i have:

Code:

:openbsd_x64
#kernel memdisk root=/dev/ram0
set memdisk http://X.X.X.X/memdisk
set src http://X.X.X.X/openbsd-image.img
imgfree
initrd ${src}
chain ${memdisk} harddisk raw
exit

:openbsd_exit
clear menu
exit 0

the output from fdisk of the image:
sudo fdisk -l openbsd-image.img

Code:

Disk openbsd-image.img: 244,5 MiB, 256376832 bytes, 500736 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start    End Sectors   Size Id Type
openbsd-image.img4  *       32 500735  500704 244,5M a6 OpenBSD

please, can someone give me some advice what is wrong.
Thanks