[johnnym]

Put dropbear SSH in and run it from inetd, see if that gets things going?

Please understand that I don't have an access problem - I always have access via serial console and both sshds (one time from an OpenBSD/sgi 6.9 userland, other times from OpenBSD/octeon 7.2 userlands) trigger the same issue for the same kernel and there are no such errors/faults for the 7.1 or 7.0 kernels - this leads me to believe the issue lies in the OpenBSD/sgi 7.2 IP28 kernel alone.

Executing sshd must touch something in the kernel (socket functionality maybe?) that makes it loose its ability to run (certain) binaries correctly.

This thread here describes something similar I think. IIUIC there the problem was a wrong assumption in the kernel code that lead to illegal instruction faults on perfectly normal binaries when the OP activated a specific option in the BIOS setup of the affected machines. It's not the same problem as I have at hand, but it's similar enough IMHO.