Hello,
Could you try connecting a LAN cable to the device and configure your PC/Laptop to have a static IP address. After that try visiting this link: http://192.168.1.1/index.html if you are redirected to that page just re-flash the latest firmware and once it's done the device should run properly. If the said page is not reachable try using a different power supply and check if the device will boot up properly.
Thank you and have a nice day!
Regards,
Jerome