About the "Fast MMU Access" error:
<beware because="these could be rumours">
What I understand for the problem is that the sysvinit source code
is fine, but for Sparc generates the compiler executable code that
uses registers that are not available in all Sparc CPUs.
</beware>
Sounds like heavy rumor. The Fast MMU Access occurs well before init is
executed, if I recall correctly (by the time init is called, traps are in
place that would trigger kernel code in the case of this hw error).
Most of what I have heard is in relation to first-cd.b bootloader and
Ultra III's. Since I don't have an Ultra III, I can't do any testing.