Take the gc controller apart and right beside the 4 directional pad you will see the connector for it, its black and has legs that can be soldered i can't really explain what it looks like, But i just covered it in solder than put the controller back together, It was a crapy controller by the way, now when i stick it in, It automatically boots to recovery without hitting any keys, I guess thats what your asking for?
I believe holding reset is a feature of preloader. It automatically loads the HBC on boot. Holding reset will go to the config screen and allow you to choose something else to boot (someone correct me if I'm wrong). So if a bad wad causes a banner brick, you can boot the HBC and wad manager and remove the bad wad.
Im gonna beat you to it
Marcan said in a different forum "The dongle stuff was reverse engineered from the system menu. It's just an EXI device with ID 0x070200xx. There's nothing more to it, the system menu only checks the ID."