Can I do factory reset Xiaomi Gateway 3 in developer mode?

Hi, all

Now I’ve been trying to bind my Xiaomi Gateway v3 to Mi Smart Home Binding.

So in Mi Home App, I switched the gateway to developer mode and enabled wireless communication protocol.

And then somehow I saw the gateway was online in the Paper UI but couldn’t add child devices.

So I tried factory reset, removing the related list in Mi home app and Paper UI.

But after that, even pressing the button on the gateway over 10 sec, it doesn’t seem to be reset, and I cannot even scan the device in Paper UI and Mi Home App.
It just flashes blue light about 10 times and I have no idea what it means.

Is there anything I should try?