I'm sorry for my mistake
it's BootROM 4.2.9 i have and not 4.2.1

1/ How to make a bootable CD image?
mkisofs -J -r -L -l
and
mkisofs -J -r -L -l -hfs
aren't bootable with
'>boot cd:,\ofwboot.elf netbsd.ram.gz'

2/ when i copy the CD on HFS partition and boot it ('>boot
hd9:,\ofwboot.elf netbsd.ram.gz') it stops at 'Console Keyboard type:
USB'.
What is a ADB keyboard ?
How to fix that error i will see again if i succeed booting from network
?
(titaniumG4-550)

thanks in advance