11.0 RC1 kernel panic, how to get to the debugger?

[Rudi]

Hi list,

did some more research and found bug 196497
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=196497

I wanted to verify if that bug is what I am seeing.
The description is not clear on what to do exactly, but after consulting
https://wiki.freebsd.org/Newcons

I decided that getting to the kernel debugger and typing
ddb: set vty=sc
ddb: continue

should do what is not spelled out directly. Is that assumption
correct?

However, I seam to be unable to get to the kernel debugger in the first
place.

How to repeat:
================
in open firmware
0 > boot cd:,\ppc\loader cd:0  //as per FreeBSD Handbook chapter 2.4

at the loader "hit return or wait 10 sec" I hit space, which gives the
loader prompt:

OK

https://www.freebsd.org/cgi/man.cgi?query=loader&apropos=0&sektion=0&manpath=FreeBSD+11.0-RELEASE&arch=powerpc&format=html

Unfortunatly makes not clear what to do exactly with the "boot_ddb"
variable.
set boot_ddb //
set boot_ddb=YES  //
set boot_ddb=1  //
set kernel_options=boot_ddb // and then
boot

All 4 fail the same way: the kernel loads, probes devices -at which
point it is clear the variable did not take effect- and then
ultimatly panic and reboot.


Expected behaviour:
===================
right after the copyright notice, befor any device is probed get:
ddb:



What am I missing? Enlightenment welcome.

/Rudi