I’m using Google translator, I apologize for my bad English.
I would like to know if there is any way to go back to firmware 3 after I have updated to version 4 beta?
If the user adds a device to the VPN exclusion list the DNS configured on the router is not applied for that device, this is just one of the many issues in version 4.
Many issues could be the result of the name ‘beta’.
I think uboot is what you are searching for. But it is very depending of the device you are using: Advanced Uboot - GL.iNet Docs
Mist times: unplug power, press some button, wait until something is happen to the lights and release the button … but this may vary. It would be helpful to know your device.