The replacement amp that Axiom sent me had the original firmware. The only thing that is different in my 600 now is the driver. I have the driver that is made with dull rather than shiny aluminum. The dull aluminum doesn't go as well with my beaver \:\) . I replaced the driver due to noise at lower frequencies with high SPLs. The noise is no longer there.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated