I currently only tried doing so on the Dreamcast logo/loading screen as I was attempting to see how speedy it could go on Shield TV. (knowing that Fire TV Gen1 was pretty darn fast aside from being unusable with stand-alone Reicast due to hardware panic)
Edit; It also “hangs” on a game,in this case it freezes the image on Sonic Adventure 2 but I can still hit controls to make it move on,so its actually freezing the image,even to the point where the RetroArch menu won’t display when you open it,forcing me to press Home to escape it. Sorry for making another topic so soon about another thing,this is a pretty nasty issue for the Flycast core though if your finger slips and hits whatever fast forward is mapped to by the user.