This Flex QSB was designed for use with the Pluto-IIx XC3S200 HDMI which is a pre-programmed development board with the GCVideo 3.1 that takes the Digital Signals from the solder points of the Digital Port on the Game Cube DOL-001 and converts the signals into 480P DVI signal that is output through an HDMI socket which is an acceptable signal for most Televisions.
GCVideo Info and Code can be found on the Github link: https://github.com/ikorb/gcvideo/tree/main/HDL/gcvideo_dvi
Normally this mod requires around 20 wires soldered into the Pluto-IIx XC3S200, the Flex QSB eliminates 18 of those wires and only requires 2 wires which is 5V power and the Controller Signal making this a much easier and faster method to install this mod.
The Pluto-IIx XC3S200 can be bought at the following site: https://www.knjn.com/ShopBoards_RS232_Parallel.html (Choose Item#6117)
Installation Video and 5V/Controller Solder Point: