For those waiting for a ColdFire update to support the latest Firebug, Nathan Mische has released a fix. He goes into detail here about some of the internal changes. If you want to find the latest Firebug, it may not be terribly easy to do so. The GetFirebug site doesn’t mention the newest release (as far as I know). You can find the release here: https://addons.mozilla.org/en-US/firefox/addon/1843. To be clear, the release you want is 1.2.0.b4. The UI is a bit different so you may need to click around a bit.
As a side note - I noticed that Railo also uses debugging templates that you can edit. They look pretty different from the Adobe CFMX versions, but they are readable (not-encrypted). It may be possible to add ColdFire support to Railo.