Deleting the preinstalled maps via a hack?

It appears that the preinstalled maps are all stored as files on the inReach Explorer+.

The file system for the inReach Explorer+ shows up as a drive letter only during a long map sync.

It appears possible to browse/copy/delete files from the device if it is doing a long map sync.

I have copied off all the preinstalled maps, but want to know if anyone else has tried to delete them. Did it cause any problems?

Has anyone tried to free up space by deleting the preinstalled maps? I would rather use the OSM maps than the built in maps and I don't like having to constantly add/remove maps because there is not enough space to put all the preinstalled maps and the OSM maps for the us on at the same time. 

I drive/hike/fly all over and would rather not have to be adding removing maps before each trip. Sometime I don't know exactly where the trip is going.