How do you open the 612 trunk(boot) when the button fails?
There is a pull cable accessed behind the flap behind the arm rest in the rear seats. Pull down the arm rest, pull up the velcro flap and you should find the cable behind that.
Does the remote control unlock button of the trunk work? If no: it is not the switch in the car it self. Verstuurd vanaf mijn G3121 met Tapatalk
If its anything like the fuel flap solenoid in my 355, it starts to stick and a little WD 40 usually fixes it right up. I havent had an issue on my 612 so never checked.
Note that if power has been disconnected you need to lock/unlock car once before trunk open on remote works again.