Select target board in platform_config.h file. 
Default is TEECOMPUTER. 
Comment out for MCUMEVGA (see wiring in schematics subdirectory)
Soldering the PSRAM (PT8211) below the Teensy4.1 is mandatory!!!!

All compiled with Arduino 1.8.19 + Teensyduino 1.56
Chose optimize:smallest code and USB keyboard layout if needed. 

Default CPU speed 600MZ except for TeenyUAE and TeensySNES that need 816MHz.
TeensySNES has USB disabled!