Before downloading any firmware files, it is vital to know which chip your X20 Mini uses. Manufacturers frequently change internal components without changing the product name. Turn off the device and remove the MicroSD card. Check the system information menu in your stock settings.
The custom firmware scene for the X20 Mini is built around a few key sources that are considered the "Top" choices in the community. These are the most stable and widely used firmwares available: x20 mini custom firmware top