Also in HK with US N900. Same problem here. PR1.1 appears to have fixed most problems with GPS lock but map is off by what appears to be a constant amount. Sometimes it will be correct for a few seconds and them jump back. All other mapping apps track accurately.

Are you downloading maps on the fly or did you pre-load them ?
If you pre-loaded them did you use Map Loader or install them
manually ?

-Jonan