Problems booting head on G4 Powerbook

[Michael Tuexen]

Dear all,

I did a self host build and install world of an svn revision a couple of days old.
Now the system does not boot anymore. It reports:
>> FreeBSD/powerpc Open Firmware boot block
   Boot path:    /pci at f4000000/ata-6 at d/disk at 0:
   Boot loader:  /boot/loader
   Boot volume:    /pci at f4000000/ata-6 at d/disk at 0:3
Consoles: Open Firmware console

FreeBSD/powerpc Open Firmware loader, Revision 0.1
(Tue Aug 28 02:08:04 CEST 2018 tuexen at pb15)
Memory: 1048576KB
Booted from: /pci at f4000000/ata-6 at d/disk at 0

-
Invalid memory access at     %SRR0:   00000000     %SRR1: 00083030

Apple PowerBook5,2 ....

Any idea what is wrong and how to fix it?

Best regards
Michael