The NetBSD/hp300 port is unable to run executables from any of the other m68k architectures because it uses executables with a 4K page size. All the other m68k ports use 8K pagesize executables. There are 3 other m68k ports (sun3, amiga, atari) that use a HARDWARE 8K pagesize, and will never be able to efficiently run 4K executables.
As a result, OpenBSD/hp300 was changed to use 8K executables as well. For compatibility, it can also run the old 4K executables. No measurable performance losses or filesize increases are incurred by using 8K pagesize executables.
www@openbsd.org