is there no way to reset the offset? there are at least three of us in this forum that use the Garmin Zumo 660 or its BMW variant, the BMW Motorrad Navigator IV. Though Garmin, as a closed and rather antiquated proprietary system, remains the antithesis of open source and compatible standards, we have been able through their China distributor to recalibrate the map to compensate for the China offset. We've all had this done at the Shanghai office. They take your GPS into the back, then go up on the roof. They won't let you accompany them when they do it. They are all secretive about who does it and how. But it gets done.

Mine is accurate down to a couple of meters at most, though that hardly helps when the road you are riding opened only last month and isn't even in the map.....

Any cryptographers in MCM?