@marionline There's no other way to get those to work than to dig up the code provided by the seller and use it. ?
Now, most sellers actually provide the same HW and code (a bit like most 2x16 LCDs are variants of the HD447xx), so if the display has any markings, the code should not be too hard to find from there.
A caveat though: the way it's provided, it'a either LCD or HDMI. Switching requires a manual operation, and having both displays work independently is not supported.