This project looks interesting. I saw you use stty to configure the console, but there is a native "UNIX way" to do this via tcgetattr/tcsetattr, you'll have to figure out how to use these C functions elegantly in Go though / if there is some Go package which wraps them already. On Windows you'll have to configure the console via win32 API calls GetConsoleMode/SetConsoleMode and again you'll have to figure out how to do this from Go ⇒ you'll have to add some compile time switch between "UNIX like" OS and Windows to support both. The "UNIX like" version should work on Linux, macOS, and various other UNIX like systems.

You could also improve the debugging experience with full execution trace recording (record all executed instructions / memory accesses / … to a trace file) which would not only give you detailed information about what exactly went wrong if something goes wrong but also allow you to directly debug your own Z80 code on assembler level.