I have PC164, with ev56 cpu. But older milo's did not turn on
the new BWX instructions, because botherboard does not support IO with
the new instructions. So far all was well.
The new milo-980602 did actually turn on the BWX insns. All was ok
until I compiled egcs-1.1 and kernel with it. The egcs-1.1 configure
did recognize that the instructions were enabled and compiled for
alphaev56. All userland programs compiled with the egcs did work.
But the kernel compiled with it hung just after "jumping to kernel".
Everything returned to norm when I recompiled the kernel with -mcpu=ev5,
so I assume the problem was BWX on IO space.
I actually noticed that programs were compiled for ev56 with BWX insns,
when I tried to bood with older milo - all the programs started to
give "illegal instruction".
Conclusion. If you have PC164 and installed the latest milo and compiled
egcs with it (for ev56), compile the kernel with -mcpu=ev5, and don't return
to older milo.
Alexander.