If the panel keeps showing "connecting," and does not respond at all. Please turn off the machine and reflash the SD card.
1. Remove the screw and open the right cover.
2. Find the micro SD card on the mainboard.
3. Download the ISO file(Firmware 3.2.6) that needed to be burnt to the SD card from the following link.
4. Flash the ISO file to the SD card with burning software.
There is no need to format the SD card before the burning process.
5. After reflashing the SD card, upgrade the firmware to the latest version.