Bruno, can you send pictures of this router without it's cover?
I'd like to see how the antennas are connected to the board.
Also, do you know if the antennas are bi-band or the 2.4Ghz antenna is
inside the router like in other models?
Here they are. It looks like both antennas are connected to both chips (there is a track in the other side of the board connecting the antenna on the left to the MT7620 chip).