Great idea and seems to work as intended in KOTOR 1, though with two caveats that may or may not be related to this mod.
Every time I use the armband, I get a message that says "Unable to reach target!" Not sure if this is a bug or not but at least it lets me know the armband was triggered.
Using the armband will reveal the full map on the menu map screen only. The UI overlay map does not change no matter if I use the armband multiple times or even if I leave the area and come back. However, using the revealmap cheat has the exact same behavior so I don't think this mod is the issue. Sadly, my main reason for wanting to use this mod was to remove the fog from the overlay map so it's disappointing to find out neither the armband or the cheat code work for me.
Note: I have this installed on top of the KOTOR 1 full mod build - https://kotor.neocities.org/modding/mod_builds/k1/full including the widescreen and hires menu and UI mods.
EDIT: Removing the mod files (and spells.2da) from the override folder and reinstalling the mod seems to have fixed all of the issues listed above. The armband works perfectly now and both maps are updating. (Not sure if I messed up any other mods by deleting spells.2da but I'll deal with that if/when the time comes.)