> ofwboot is unable to load a kernel. I'd suspect build environment.

 I had that thought too, since I did have a panic once during a build, and I
had been using the sparcv9 optimization flags to gcc.  That's why I removed my
tooldir, /usr/obj, the gcc flags (just "-pipe" now), and rebuilt everything.
And then after that I tried cross-compiling from a working i386 box.  None of
that seemed to make a difference.

 I'm trying to upgrade my bootprom to 3.31 now using Sun patch 106121-18,
but it's failing like:
   loadfile: reading header
   elf32_exec: Booting /pci.....
   .......449a98Illegal Instruction