Premacy Radio Unlock

Hello, I bought a Premacy as a new vehicle last year. Now I had to cut the radio short from the net for an installation of an antenna softener. After connecting to the on-board network the radio demanded a code to my amazement. Since I had never entered a code, I took over the specification ‘—–‘. The radio acknowledged this with the message ERR. Lt. Statement of my dealer the radio must be sent in and the whole action costs then around 90 €. On my W ider statement, that I would never have entered a code and therefore no blame would be on me I got the lapidary answer, that a computer would crash and that could be the case with the radio. I would have had bad luck now. My question now, there is really no other way to put the radio back into operation. Greetings