@joinski for dreamcast.
as a general rule, just remove /userdata/system/configs/<emulator> (and reboot, soon no more needed). to avoid a reinstall.
yes, bios was fixed but requires 2 files to be aligned, and thus, the removal of some config data is mandatory (remove /userdata/system/configs/reicast and rebooot is enough)
for the rest, strange that you had to reinstall. can you reproduce to generate a log ?
for the ratio, there are several parameter that affect it. the tv ratio supported, params, and reicast bugs about ratio. hard to know where is the problem. the only configuration in batocera is
https://github.com/batocera-linux/batocera.linux/blob/master/package/batocera/core/batocera-configgen/configgen/configgen/generators/reicast/reicastGenerator.py#L55
if system.config["ratio"] == "16/9": => 16/9 in es, then, we force rend.WideScreen to 1, else, it is automaticly configured by reicast (and possibly buggy)
When you set Emulator to Libretro and leave Core at "AUTO" then games do not start (black screen, then it goes >>back to ES Menu). So i would suggest to remove "AUTO", when Emulator is set to Libretro.
i agree that this is a bug. but i'm not sure about the correct way to fix. i'll analyze better. i mark it inmy todo list for 5.23
At default with everything under Game Settings/Advanced/N64 on AUTO the resolution is 640x480 and the image is stretched to 16:9 aspect ratio
i think it depends on the tv. i will do more tests, but some tv stretched by themself and i can't really do things like i don't know howthe tv will behave.