Hi,
I don’t think this is an issue that could be fixed by the plugin.
Here’s some things to check:
1. Clear the Firefox browser cache
2. Switch to a standard theme and deactivate ALL other plugins
3. Upgrade to the latest Firefox/iOS
4. See if you can find a javascript console in Firefox in order to see any javascript errors
My guess is that the Google Maps API doesn’t support that combination of OS and browser. They have a list here:
https://developers.google.com/maps/documentation/javascript/browsersupport