A friends failed and we had to get his bike recovred at the start of this years holiday on arrival at Zeebrugge. The 2 scews are anti tamped and not the garmin type but the ones with an angles screwdriver slot so you can only tighten them and not untighten them so you have to drill them out. I would recomend fitting normal screws.
The failure rate of these are apparently veru high and the BMW garage near Zeebrugge keeps a good stock level for that reason.
long shaft Trox 10 screwdriver fits a treat or as alternative long shaft 2.2mm flat bladed screw driver will fit bit it probably won't have the purchase you need to loosen it. Leatherman wave smallest screw driver will fit but it too short and you'd have to strip more stuff out this all is on an HP2 by the way
apparently they aerials do fail a reasonable amount on 1200 but not as much on HP's so I got one as it's bnetter to be safe than stuck!