"Even with no card inserted you should have something on screen when you boot. Give us more info about your setup please."
Ok this evening doing some new tests, i really try hard :
My set up is a CMVS omega classic no built in save, just unibios, bought in may 2014 from the official omega shop, it goes through a scart switcher (gscartsw lite) to an OSSC, by using this set up my omega CMVS works fine with original MVS or chinese 161 in 1, with Darksoft MVS screen is black with or without micro SD, with or without menu update on the micro SD it's the same black screen, same with another micro SD no menu, no sound, no loading.
Tonight i've tested the cartridge with my another CMVS, an older MV1FZ with older unibios consolized by neooldstore, with no OSSC or scart switcher, directly hooked through RGB to a sony trinitron, chinese yellow 161 OK, darksoft MVS with or without micro SD, nothing, just black screen same as on CMVS omega.
Sorry i can't figure what' happens, i often use some krikzz everdrive, etc, but this time with this very nice MVS i can't explain why it doesn't work, not at all, it drives me crazy, i even try mailing to save your games, fast answer and very nice people but can't tell what s wrong.