No Sound after Switching Mainboard and put cfw on it

Moin Moin and Hello Humans

I have a problem with my European Nintendo DSi.
i swapped my mainboard with an other dsi that have Flipnote on it.
Both DSi sound was working fine but after swapping and flashing twillightmenu++ and other stuff the sound stop working.
Sound with Headphones working fine.
I checked allready the cables, mainboard etc. Everything is fine, nothing is broken.

Is This maybe a software problem?

ps.: Firmware is 1.4E