Some C64 ROMs do start, some don´t, why?

[bubbler]

I have several ROMs that don´t start at all. I just get the blue screen and READY, but nothing else happens.
These are T64 ROMs.
But other T64 ROMs work, they start with Load"*",8,1
Why do some start and others don´t?

[Scavy]

@bubbler concerning C64, downloading may also be... very very very long ^^

[bubbler]

@Scavy The thing is, loading does not even start. Nothing happens, only "READY" and the blinking cursor

[Araukaria]

Same here.
My System is a Raspy 3 running Recalbox 9. Since the update from 8 to 9 none of the C64 Roms ist running properly.
Most of them don´t start anymore. The few ones starting, have a cracked sound and are running slowed down.
I changed the Emulator in the configuration menu several times, the problems stay the same.
All other systems are running properly.

[artman5]

@Araukaria
Had same issue with c64 games. Seems to work if all bioses are pressent using libretro vice_x64 emulator running on rp3b+.