Install the Allwinner USB drivers on your PC.
Stock firmwares often include pre-installed apps that eat up the limited 1GB or 2GB of RAM typical of H313 devices.
Many H313 boxes ship with a "Tablet UI" (standard Android). Custom ROMs often port the Android TV (ATV) Leanback Launcher , which is much easier to navigate with a remote. Allwinner H313 Custom Rom
Downloaded specifically for your device model. The General Process:
Custom kernels can sometimes help the device run cooler, preventing thermal throttling during 4K playback. Install the Allwinner USB drivers on your PC
Advanced users can gain Magisk or SuperUser access to tweak system performance.
Custom ROMs will not give you "Official Netflix 4K" if the device lacks Widevine L1 certification. You will still be limited to SD or modified HD versions of streaming apps. Conclusion Custom ROMs often port the Android TV (ATV)
Check forums like FreakTab or 4PDA (Russian, requires translation) for specific ports. Developers often release "debloated" versions of the stock firmware that retain original hardware drivers while removing the "junk." How to Flash a Custom ROM on Allwinner H313