Apps accessing external SD

[mrw82]

I have added the hema explorer app (for android) onto my android head unit, but in trying to download the map files I am unable to save them onto the external SD card and will only let me save them on the internal memory, which does not have enough space.
The app automatically creates a root file, but there is options to select which drive to save it to. But the app isn't detecting the external memory (SD or GPS card slot) so only gives the internal memory option.

The app developer is blaming the device, is there any way I can get around this?
Thanks.

[Jammy]

Hi, the map files can only be installed into the GPS card and save them on the internal memory, you can download the app into the sd card, normally it will automatically save on the 1GB machine memory, and you can manually remove it to the inner memory of the sd card, but it can not be installed and saved on the external memory, hope you can understand.
Regards