No rebinding is required. The device upgrades will not have any effect on your account binding. The firmware upgrade is successful, the device can work well after restarting.

The possible reasons are as follows:

1. Check the WiFi network

2. Shut down and reboot your device

3. Re-setup the device ( After the device is powered on, scan reset QR code within ten minutes ) , Rebind the device.

When making a call, please try to keep the mobile phone more than 10 meters away from the device. The echo and howling caused by the short distance call is a normal phenomenon.