Click Check for update . If the firmware is available, you will see the download size (typically 300–500 MB).
The Xiaomi Mi Box S remains one of the most popular Android TV boxes on the market, praised for its balance of affordability, 4K HDR support, and a clean Google-certified Android TV experience. However, like any streaming device, its performance heavily depends on regular firmware updates. Xiaomi Mi Box S Firmware Update
Navigate to Settings (the gear icon in the top-right corner of the home screen). Click Check for update