[LinuxBIOS] NMI debugging tool ?

[Quux]

Yo!

http://www.pcisig.com/reflector/msg03869.html

I was thinking the same ...  
even though I am aware of the fact that ROM debugging is hardly possible 
in an early state (no RAM set up yet) I still wonder about the 
feasibility of a debugger in ROM. or does it not help much more than a 
regular Linux debugging kernel and is thus hardly worth the effort ?