Bricked tablet save iplay50 (T1030)

my iplay 50 tablet is bricked, now I want to flash official firmware via research download.

So I connected the tablet to USB while holding vol- button, but my pc could not recognize my device, any advice? Thank you so much

Open the device manager that comes with the Windows operating system. After the machine is shut down and you press and hold the volume down key to connect to the computer, there will be a new device in the device manager. If the driver is installed well, there will be a sprd port.
If there is no response at all in the device manager, check the connection problem.

thanks, now recovered