Hello,
this project and OpenStreetMap4Primer2 1.0 (http://www.stm32circle.com/projects/project.php?id=75) are quite similar. Therefore I will skip on OSM4Primer myself. FR4 did a great job.
Integrating UTM conversion will include the only feature of Locus not covered by to OSM4Primer.
=> Locus is not developed any further.
Regards.