NetBSD-9 on 80486?

Hi,

I'm trying to boot NetBSD-9 on an ISA system with a Cyrix 486DLC. The 
system boots NetBSD 4.0.1 just fine:

https://www.klos.com/~john/dmesg_cyrix_4.0.1

I've compiled a NetBSD-9 LEGACY kernel as well as a custom kernel without 
ACPI (also tried COPTS="-march=i486"), but all kernels I try to boot 
(using the 4.0.1 bootloader) hang right after they finish loading:

5451728+95136+670816 [429136+342778]=0x6aac58
(hangs)

I know gcc, and therefore NetBSD, stopped supporting 80386 CPUs due to the 
lack of certain atomic instructions, but I thought 80486 CPUs were still 
supported.

I also tried NetBSD 5, 6 and 7 kernels, but they do the same thing. It 
seems that "vga0 at isa?" was removed before NetBSD 8, so I'd expect them 
to work.

Any ideas?

John Klos