Unplug everything. Reconnect only the HDMI and power. The first boot after flashing takes 5–10 minutes (this is normal). Do not interrupt it.
: Format a USB stick to FAT32 and copy the downloaded .apk or firmware files into the root directory. Evpad 5s Firmware Download
For the 5S, you should look for apps under the series (e.g., HX Live, HX VOD, HX Playback). Unplug everything