Quote Originally Posted by JackFlash View Post
My questions (pls pardon the techno-idiocy in them) on installing Phil. maps are these:
  1. If I installed both Roadguide and OSM, how will I know which one is being displayed by the device? Can you switch from one to the other? When I was abroad, it was quite intuitive since I was only relying on the pre-installed maps.
    Yes, you can select which map will be displayed. If you enable both maps, I believe in some units you will see both maps so that if the tracks are misaligned you'll see two roads, while others will show only one map depending on their so called FID or which map is saved where, internal memory or sd card.


  2. Will overwriting the "gmapsupp.img" file on the device affect any of the pre-installed maps?
    No. The new gmapsupp.img will only overwrite the old gmapsupp.img. Pre-installed maps on new Garmin units have different filenames, e.g., gmapprom.img (U.S. Map) and gmapbmap.img (World basic), so they won't be overwritten. But as always advised, backup all files of your unit before tinkering with it!
Thanks for the help!
hope that helps