There is a way to pass memory parameters to xvic core?
The RAM configuration does not appear to be implemented via the retro_set_environment, which I think is required in order to select different RAM expansion. Unfortunately most of the great Vic20 games require RAM expansion.
I am also finding that the keyboard mapping is a bit odd with the xvic core - specifically the return key is mapped to the ` key - there are also other oddities with the keymap which do not appear in the c64 core for example.