Do you know that from the vendors manual or is it just how you guessed it?
I have several devices with multiple features on the same action.
One will blink once after 5 seconds on press and it means that if I release it there, then the network configuration will be deleted and the device will go into fallback mode.
If I keep it pressed 8 seconds, then it will blink once more and if I release it then it will factory reset the device.
If I keep it pressed 12 seconds then it will start to flash and it then means it have gone into firmware flashing mode.
If I had no manual then I would probably not realize the 2 first modes were there and I would assume the last one was for some repairing/reset mode.