in the case of Pentagon128 - BDI is not option, its on main board.
Kempston joystick IF and AY-3-891x sound is optional, they are on additional board, which may be or may not present in machine.

geecab,
I can's see big problem here, except Kemston is not emulated for Pentagon128.
I've loaded Dizzy3 tzx, pressed 0 - controls seems fine as Sinclair joy.
btw on current git build it works for spec128 too.