well, permanent damage being defined as 'overwrites some of it' ... it 
can be overwritten again.. a while ago there was a thread about this, 
some folks took dumps of a pristine 4k90 rom, and these can be written 
back in again. it'd be tedious manually, of course.

On Sun, 10 Mar 2002, Lieven Blancke wrote:
> Hey, I am really disappointed here! NetBSD puts this hardware on their
> "Supported System Models" list, and it does permanent damage to the PROM?
> Somehow, I feel ripped off.
> 
> Is this PROM damage really an issue? When I type "boot" NetBSD seems to work
> OK.

i dont know if it causes real problems.. i'd suspect that it is a case of 
not hitting the conditions under which the clobbering will lead to 
failure, but it probably isnt a very good thing to be overwriting some of the
roms.. 

isildur