panic: trap type 4, code=0, pc=ffffffff8219649a
Starting stack trace...
panic(ffffffff8271c311) at panic+0x155 sys/kern/subr_prf.c:229
kerntrap(ffff80002659b7a0) at kerntrap+0x1b7 sys/arch/amd64/amd64/trap.c:327
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
ktrops(ffff800023b568a0,dead4110dead4110,0,80000044,fffffd807e264048,fffffd807f7d77b8) at ktrops+0x4a ktrcanset sys/kern/kern_ktrace.c:696 [inline]
ktrops(ffff800023b568a0,dead4110dead4110,0,80000044,fffffd807e264048,fffffd807f7d77b8) at ktrops+0x4a sys/kern/kern_ktrace.c:541
doktrace(fffffd807e264048,4,44,0,ffff800023b568a0) at doktrace+0x514 ktrsetchildren sys/kern/kern_ktrace.c:566 [inline]
doktrace(fffffd807e264048,4,44,0,ffff800023b568a0) at doktrace+0x514 sys/kern/kern_ktrace.c:488
sys_ktrace(ffff800023b568a0,ffff80002659bae8,ffff80002659bb30) at sys_ktrace+0xd2 sys/kern/kern_ktrace.c:529
syscall(ffff80002659bbb0) at syscall+0x446 sys/arch/amd64/amd64/trap.c:599
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x4fa1dbefa50, count: 249
End of stack trace.
syncing disks...21 17 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  giving up

dump to dev 4,1 not possible
rebooting...
SeaBIOS (version 1.8.2-google)
Total RAM Size = 0x0000000080000000 = 2048 MiB
CPUs found: 2     Max CPUs supported: 2
SeaBIOS (version 1.8.2-google)
Machine UUID 969d4b26-6dee-2bb7-7d35-48434919f208
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f2480: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.55
boot> machine ddbcpu 0
machine: syntax error
boot> trace
|/-\|/-\|/booting hd0a:trace: -\|/open hd0a:trace: No such file or directory
 failed(2). will try /bsd
boot> machine ddbcpu 1
machine: syntax error
boot> trace