mount root file system (memory disk within kernel), sandpoint port

[netbsd <netbsd%scentech.ch@localhost>]

hello

during mounting of the root file system I get a trap. Any help yould be 
appreciated

-is it enough to copy the kernel into the ram? or do i have to unpack 
the memory disk fs somehow?

I created the file system as big endian ffs and put it into the kernel 
with mdsetimage. I have also enabled the following kernel options:

options     MEMORY_DISK_HOOKS
options     MEMORY_DISK_IS_ROOT    # Force root on RAM disk
options     MEMORY_DISK_ROOT_SIZE=4096    # 2 MB

pseudo-device    md        1


an extract of the console output:
=================================
md0: internal 2048 KB image area
boot device: <unknown>
root on md0a dumps on md0b
mountroot: trying ffs...
trap type 200 at e2834
Press a key to panic.
panic: trap
Stopped in pid 0 (swapper) at      0xd0360:     lwz     r0, r1, 0x14


environment:
============
CPU ppc 750, 400MHz, 64MB RAM, Flashdisk
Netbsd 1.6.2, based on the sandpoint build


thanks

Stefan