This is how I installed and tested the GENERIC-17 kernel.

1) I started the Installer utility.
2) I clicked the button for the hard drive with the NetBSD filesystem on
it, and clicked OK. Then I chose Mini Shell from the File menu and typed
"rm netbsd" and hit Return at the prompt. (This makes sure any old
kernels are gone.) When it was done, I typed "quit" and pressed Return.
3) I chose Install from the File menu.
4) I used the dialog box to navigate to the folder with the kernel I
downloaded, and select it. I then clicked the Add button. The file's
name was displayed in the bottom box. Then I clicked Done and the
Installer installed the kernel.
5) I opened the Booter, chose Booting... from the Options menu, and in
the dialog box, clicked "NetBSD/mac" and entered "netbsd" as the kernel
name. In the "Root SCSI ID" box, I entered the SCSI ID of the hard drive
with my NetBSD partition on it. Then I clicked OK and chose Boot Now
from the Options menu.

For me, anyway, it crashes right after the screen goes white and I see
"[preserving (some six-digit number) bytes of netbsd symbol table]" with
a cursor under it. (Hope it works better for you!) If you get past that
and can boot it okay, please email me back telling me how you did it.
Thanks!

John Plotecher
jplotech@diisd.k12.mi.us