Hi
MPS record 0x46 ('F') contains family name and FID/PID values. Record 0x50 ('P') contains FID/PID values and some flags. 'P' could mean "Product".
We have an F record but not a P record. I believe that P is a newer record, as it is not present in gmapsupp produced by early versions of mapsource - or perhaps there is something that has to be present in the input to make it appear.
The name "mp4" is placed in img header. In my opinion it should be repeated in MPS subfile as a record 'V'. I think Mapsorce and Mapinstall do that.
We add a V record, it defaults to the string 'OSM map set'. This can be changed with the mapset-name option (which has to be written as --x-mapset-name='hello world' as it is not in the options file). So I suppose that 'OSM map set' is not appearing and maybe it needs the P record to be present for it to be used? ..Steve