Who know.
As in Linux an environment start of kernel Netbsd differs from attempt to load and execute netbsd as ELF file.

I install in my SCPH-75008 modchip and laser head protection. It has allowed to start and use soft with DVD-r 
disks written down by me.
I get dvd image uLaunchELF and burn DVD-r.(http://www.ps2-scene.org/forums/showthread.php?t=37242)
Boot playstation from that dvd.
Then i try load and run netbsd kernel compiled as elf for ps2 from umass device and ......? black screen on 
tv :) 
Load fail or not ? How test?
Thanks.
PS 
Sorry if my english not clean.