Because the H616 is a low-cost SoC often used in "no-name" generic TV boxes, major developers often skip it. There are rarely "AOSP" (Android Open Source Project) builds like stock Android available for these boxes.
: Known for its smooth performance and "stock" Android TV feel. allwinner h616 custom rom upd
If you own a generic $30 TV box, a custom ROM transforms it from a laggy advertisement machine into a snappy Kodi box or RetroArch station. The process is more fragile than Rockchip or Amlogic, but the performance gains (30-50% less RAM usage) are undeniable. [GUIDE] Allwinner H616: Full Custom ROM Update Walkthrough