This sort of follows the compiling the kernel thread: I just supped
the -current sources, and have the ftp.ph.kcl.ac.uk comp set and
kernel installed. I recompiled make and config and configured a kernel
which built OK. It boots, but now I can't use the old binaries and get
the likes of

Undefined instruction 0xeca0420c @ 0x00006a20 in process login
LDC/STC
stc	p2, c4, [r0], #0x030!

In the configuration I included
options         COMPAT_43       # 4.3BSD compatibility.
options         COMPAT_13       # NetBSD 1.3 compatibility.
options         COMPAT_12       # NetBSD 1.2 compatibility.

So, have I missed a compatibility option? I should be able to build
the new userland with a new kernel and old compiler right?

Cheers,

Patrick