Yes, it might be worth a careful hack, there are several folks you have wire-or-ed in a serial link, as in the Pi item.
Be very mindful of levels and ground loops. The serial link on J14 is a direct connection to the microcontroller. The microcontroller is not tolerant to 5V logic.
If the FTDI device has failed, it is somewhat difficult to predict if it’s serial out leads remain high impedance
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