No, they don't block OSM maps. files. I don't even think that would be possible because they still use the same map format as with previous devices. OSM maps files work without problems on Garmin etrex 20/30 even with the newest firmware (currently 3.40). For more information see the [Garmin][1] and [Garmin/eTrex_series][2] wiki pages. [1]: https://wiki.openstreetmap.org/wiki/Garmin [2]: https://wiki.openstreetmap.org/wiki/Garmin/eTrex_series

No, they don't block OSM maps. I don't even think that would be possible because they still use the same map format as with previous devices. OSM maps work without problems on Garmin etrex 20/30 even with the newest firmware (currently 3.40). For more information see the [Garmin][1] and [Garmin/eTrex_series][2] wiki pages. [1]: https://wiki.openstreetmap.org/wiki/Garmin [2]: https://wiki.openstreetmap.org/wiki/Garmin/eTrex_series