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@dieuy Have you tested it on another TV?
Have you tested with another HDMI cable?
@spyhunter10 Do a clean install of the latest version of Recalbox and try again:
Did redoing the installation solve the problem? If not, what hardware are you using? Are you using the correct BIOS? Is ROMSET correct? Have you tried changing the emulator / emulation core?
To avoid problems with Arcade games, read:
For God Knows which reason, retroarch defined buttons like :
1 -> B
2 -> Y
3 -> A
4 -> X
Which is totally illogical with their idea of A to validate and B to cancel (thus making it work with any pad).
BUT : you can use the "core remap" feature : buttons will be remapped according to how you set them up. You do it once for all for every 8bit core
For now it's not officially supported.