Voices stop working after GPS signal is obtained

Hello, everyone.

I'm having some strange problems with my TomTom One XL.

I installed the 9.510 32 MB version of the NavCore on both, SD and internal memory, and the computer voices work on the internal memory (doesn't matter if there is GPS signal or not) but when running from the SD, the voices stop working as soon as it gets a GPS signal. Tried searching for the solution but didn't find anything.

Map used on the internal storage is an original Iberia map of which I don't even know the version.
The SD card contains ES/PT and major roads of WE (which was used in the testing), and Central Europe 945.6174.

Adding some more info about the system, hope it's worth anything
OS 547200 (2039, 4/4/2013)
GPS v1.20

Is the setup on the SD card 100% identical to the internal setup?

And: You can try the version with "soundfix" from the installer to check if it gives you the sound back.