Well, if I understand you correctly, you were saying that doing the following would reset your Radio back to factory:
- Remove the battery
- Press and hold the Home key
- Insert the battery
- While still holding the Home key, press the power button on the Radio.
I tried this, and it did not reset anything.
HOWEVER,
If you hold the top 2 buttons down, while powering on the DTR, it goes to a flashing menu that looks like this:
Not sure what to do with that screen, but maybe it lets you re-flash it?