I recently bought an apple G4 400mhz zif on ebay.  it was pulled out of a yikes G4 and I will be installing it in my B&W.

what i'm not 100% sure about is if the sonnet patch will work on non sonnet zifs.  i'm sure it would work fine as it just a simple firmware patch to allow a B&W to use a G4.

I really want to use the sonnet firmware as its the only one that can be removed.  you never know..  when I upgraded my other B&W to a sonnet G4 500 I later tried the old G3 zif and it didn't start.  if this G4 zif ever blows up on me I want to be able to use the old G3 400 again so it would be nice to remove the G4 patch.

any thoughts would be great.

Of what i understand of the patches for the B&W's is that you need the most recent firmware then from there you can use the G4 unlock patch (to be able to use the G4 zif's on the B&W). As for removing the patch, once installed, you don't need to remove it. I have used a G3 before with the patch and i was able to swap the G3 and the G4 zif's without a problem and still have the machine boot and run properly. All the G4 enable patch is is software that is loaded into the e-prom that tells the motherboard that the unidentified G4 chip is legit to run on the older B&W boards.

Actually the original B&W firmware would allow the use of the G4. Apple updated it when the Yikes G4 came out (Yikes was rushed out when the sawtooth was delayed) so you couldn't steal the new chips to use in older machines.