Awesome, I'll post the settings for m3 SD in a second.
EDIT: Finally got it working on Safe Mode with no trim and _NO_ force R/W.
I tried 4xDMA, SOFT-RESET and no force R/W but that gave me 2 white screens
Anything involving Force R/W hangs my DS on the Game Loading screen.
I was using v30 firmware & loader and my test cards were an M3 SD and an M3 Lite MicroSD. Running on a Flashme'd DS and SuperKey'd DS Lite respectively.