Just for completeness, these are the test, where MAME 0.227 fails: https://i.postimg.cc/3wd437cQ/2021-01-24-18-36-03-MAME-ZX-Spectrum-spectrum.png Maybe only a slight problem coming from emulating a Z80 processor from a special manufacturer SCS instead of ZILOG according to: https://worldofspectrum....