Reviewing sizes of /bsd*, they looked odd. So after a bunch of poking and checking a new install on a new VM (which worked) I manually rebuilt the MP kernel from the SP boot. And got this:
# ls -l /bsd* -rwx------ 1 root wheel 18622131 Apr 12 18:01 /bsd -rwx------ 1 root wheel 17806667 Apr 11 00:15 /bsd.booted -rw------- 1 root wheel 10351321 Apr 11 00:13 /bsd.rd -rwx------ 1 root wheel 18532909 Apr 11 00:13 /bsd.sp However this failed to boot as well (same symptom). Eventually I did the obvious thing: copied /home/_sysupgrade/bsd.mp to / and booted that and it worked, including successful reorder_kernel. I had missed this syslog entry: Feb 25 16:48:21 o67snap reorder_kernel: failed -- see /usr/share/relink/kernel/GEN ERIC.MP/relink.log No idea what happened there. My fault for not paying attention to syslog. Sorry for the noise. John