how to save and boot a device in teethering mode

I have andriod based tv box with ethernet and wifi interfaces. I have ethernet internet connection which is connected to this TV box. I have enabled portable wifihotspot i.e. teethering(so basically it acts as a wifi router.) But every time there is a power cut to this device I have enable teethering.

Basically want to save teethering configuration so that a next reboot the device boots in teethering mode. i.e. last configured state. Thanking you for your reply.

Is there an option to save my last config on the device.