This script starts a random NES rom from your collection every 5 Minutes. You can play the game during that time, but it will automatically switch to a new rom after 5 mins no matter if input is received or not. You also have to turn the script off after usage or else a random NES rom will start after 5 mins.
Copy NES-Screensaver_on.sh and NES-Screensaver_off.sh to Scripts Directory
Make sure you're using the Everdrive Pack under "/media/fat/Games/NES/@NES{}.zip"
Also, make sure boot0.rom and boot1.rom are in the folder /media/fat/Games/NES
In your MISTer.ini, make sure bootcore feature (autostart core) is disabled.
If you are worried about SD card writes, you should not use this. I've been using it a lot and my SD card (128GB) is working great after a year of using it.