1. RetroPie-Setup
2. Configuration / Tools
3. dispmanx
4. enable
5. update at/opt/retropie//configs/pc/dosbox-SVN.conf
   • sdl
     • fullscreen=full
   • render
     • frameskip=0
     • aspect=false
     • scaler=tv2x

I’ve settled on tv2x for now. Although it doesn’t look as good as the scanlines on my Amiga. Maybe I should try dvi instead of vga. I’ll need a hdmi to dvi adapter though.