MiyooCFW VS gmenu2x

Try getting a second SD card and flashing it with the Miyoo cfw from here. It's probably something corrupted on the card.

And/or just install one of the nightly builds yourself and see what issues you find. They can be found under the actions tab on github, although I think you have to be logged in to actually see the download: https://github.com/TriForceX/MiyooCFW/actions/workflows/build.yml

Generally speaking RetroArch allows installing and removing cores, but no clue how it works on this device and what the steps are if its possible. This article or tutorial might interest you: https://github.com/TriForceX/MiyooCFW/wiki/RetroArch-Setup I think you should be able to download a core from this place https://buildbot.libretro.com/nightly/dingux/miyoo-arm32/latest/ and just put it into the cores folder in RetroArch on your device. But there might be additional steps needed to integrate them into the system, not sure at this point. BTW you should have added the name of the device into the post title. Such generic titles aren't helpful.

I have used already the cfw for this model https://github.com/TriForceX/MiyooCFW/actions/runs/4988520114

Gmenu2X / GmenuNX is a simple launcher program designed for small displays that runs well on that CPU.

This is the fork that I've worked with: https://github.com/MiyooCFW/gmenunx

I've been looking through the source code of the main menu app (gmenunx - https://github.com/MiyooCFW/gmenunx), and it apparently sets the CPU to the lowest speed the configuration allows when going into suspend mode. But for some reason that is is 702mhz. (I think the official clock speed of the CPU is 533mhz, so the 702 minimum doesn't make any sense to me.)