I tried to add a new carrier to CarrierMap.plist (see /System/Library/Frameworks/CoreTelephony.framework/Support/) but it does not seem to work. Maybe it does not work for me because the MNC code for my carrier is only 2 digits longs instead of the "usual" 3 digits? Right now I am forced to add my settings to UnknownCarrier.plist for them to be used but I would like to use MyCarrier_MyCountry.plist instead. Did anyone else on this forum try to modify CarrierMap.plist and if so, with or without success? Thanks.