> I built the NetBSD boot blocks, copied boot to /, ran installboot,
> tried to reboot...and it died with "Memory access not aligned" (or some
> similar message complaining about a memory alignment error).  So I

There is an error in installboot.c causing it to sometimes write a short
data segment into the 1st stage boot prog. I justed fixed this.


> again, and got the same error.  This time, I added a debugging printf
> to bootxx.c, recompiled, reinstalled, and everything worked.  I removed
> the printf, recompiled, reinstalled, and darned if it didn't work!

This symptom at least is consistent with the installboot bug. You pushed
the bootcode size over the next 512 boundary, which would hide it again.

> implying the attempted read size was 409600 bytes).  When attempting a
> read this large, the process hangs hard.  ps reports a D wait, and

Turns out the esp code was able to return negative residual counts...
It could also cause DMA to overrun your supplied buffer. A fix went in
this morning.

-pk