The Whistler update program has made this whole process obsolete. It is well worth the $$$.
And in fact it's now semi-dangerous to do the hack, since Whistler added a flag to the firmware (I think 3.8 and later) to disable certain features if the hardware and other factors don't match up. In that case any features beyond the original capabilities of the radio are disabled (including DMR reception) and the radio will be locked down such that you can't roll it back.
The $59 upgrade from Whistler is definitely worth the money; in effect, you end up with a WS1080 with full manufacturer support and upgrades.