MIOS supports internally Hitachi HD44780 compatible character displays
It’s ‘so called’ industry standard for the character displays, but not all “standard” displays have this particular chip.
HD44780 compatible LCD controllers:
If your LCD has one of these chips, there are good changes to get it work. These chips have similar instruction set, data bus and timings are like original HD44780 (or faster, which shouldn’t matter)
BUT this only means controller chip is compatible with the driver designed for HD44780
It’s simply easier to get a display, that has a datasheet available.
Common problems, if it isn’t your soldering:
And it’s also good to know at least HD44780 displays can be initially programmed to different character sets - maybe your dirt cheap surplus display just talks greek to you
MBHP LCD module page at uCApps.de
HD44780 Info and Links