I agree it's a bit of a mess but I don't think you have or can damage the actual RN2483 module during to firmware update process. In addition to deleting and reprogramming the firmware probably 20 times yesterday to try to make sense of the sequence of events I fussed around with least 10 retries in the following tutorial video but cut most of the attempts in the editing so I think its safe to say you will be to restore your firmware safely.. eventually.
Hope it helps.