While I remember...

With support for compressed (gzip'd really) kernels in the new two
stage bootblocks, you don't need to name your kernel "foo.gz".  The
implementation of open() in the standalone library looks for a gzip
header and will do the right thing regardless of the filename.

For example, in the 2MB diskimage available for testing now, there's
only two files in the filesystem - /boot and /netbsd.  /boot is the
normal ELF second stage boot and /netbsd is a gzip'ed kernel, just
without the .gz suffix.  This way, you don't have to type
"boot 3/rz0/netbsd.gz" or "boot -f rz()netbsd.gz" to load the kernel.

Simon.