Just place your desired CRT, PRG or D64 files on a FAT formatted microSD card and use the built-in launcher to execute them. Search for "KungFuFlash - github" for more details on this open source project.
Kung Fu Flash Cartridge for Commodore 64 - PCB ONLY
Kung Fu Flash Cartridge for Commodore 64/128 with Case
KungFuFlash Commodore 64/128 Kung Fu Flash Cartridge Various Color Case
Kung Fu Flash+Case+32GB SD Card Commodore C64/C128 NTSC/PAL Fast USA Ship
Kung Fu Flash Cartridge
Kung Fu Flash 2 KFF2 v2.01 Cartridge for Commodore 64/128 with Case KungFuFlash2
