uhmm it wasn't a joke. You really do pull the radio backup fuse. Sorry, but that is the answer.

People pull this fuse because it resets the ecu while leaving power to other things, like the stock head unit. Therefore, re-entry of the code is not required.

Depending on how you wired up your stereo components, this method may or may not cut power to your parts but it's not my fault if it does.