Below is some Beyond the Emulator Testing in the Lab.
This link will provide you the basic tools to get your Retro Handheld setup with the firmware Knulli Gladiator II. I have setup my Trimui Smart Pro and Trimui Brick.
Knulli firmware Wiki -https://knulli.org/
Tips and Tricks
This link will provide you how to Install Emudrop on your Trimui Smart Pro using Knulli Gladiator II and Crossmix 13.0 firmware.
Emudrop Github https://github.com/ahmadteeb/EmuDrop