Upgrading hboot fails: signature verify fail My Goal

http://forum.xda-developers.com/showthread.php?t=1762790

Putting jelly bean on nexus one

My Problem

Upgrading hboot   

I'm just following everything step by step (link)

$ fastboot flash hboot hboot_jellybean_260-8-168.nb0
sending 'hboot' (512 KB)...
OKAY [  0.095s]
writing 'hboot'...
(bootloader) signature checking...
FAILED (remote: signature verify fail)
finished. total time: 0.219s


What am I overseeing?
The hboot flash region is protected from accidental/unwanted/etc writes.

You need an exploit most probably.

I found this thread: http://forum.xda-developers.com/showthread.php?t=1486201