Xen is unable to find boot device

[Martti Kuparinen <martti.kuparinen%iki.fi@localhost>]

I just upgraded one of our netbsd-4 based Xen servers (sources fetched 
from anoncvs.netbsd.org 10 minutes ago) and rebuilt both dom0 and domU 
kernels and now the boot fails like this...

# xm create -c s181
Using config file "/usr/pkg/etc/xen/s181"
Started domain s181
vcpu0: Intel Pentium Pro, II or III (686-class), 2133.41 MHz, id 0x6f7
vcpu0: features bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
vcpu0: features bfebfbff<PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX>
vcpu0: features bfebfbff<FXSR,SSE,SSE2,SS,HTT,TM,SBF>
...
Kernelized RAIDframe activated
xenbus0: using event channel 1
xbd0 at xenbus0 id 1: Xen Virtual Block Device Interface
xbd0: using event channel 5
xennet0 at xenbus0 id 0: Xen Virtual Network Interface
xennet0: MAC address 00:16:3e:01:81:01
xennet0: using event channel 6
unknown type console at xenbus0 id 0 not configured
xbd0: 4096 MB, 512 bytes/sect x 8388608 sectors
Searching for RAID components...
boot device: <unknown>
root device:

At this point I can manually type "xbd0a" and accept the remaining 
defaults to boot my domU but I hear from my co-worker that even dom0 has 
this issue.

# uname -a
NetBSD s181 4.0_STABLE NetBSD 4.0_STABLE (XEN3_DOMU) #0: Wed Apr  9 
15:21:51 EEST 2008  root@xen3:/usr/src/sys/arch/i386/compile/XEN3_DOMU i386

Any ideas what's wrong?

Martti