Arduino Due 16U2 Programming Port Documentation Are there any documentation or whatsoever on what the 16U2 does when trying to program the Sam3X in Arduino Due?

I reallynwant to know what's wrong with my made up board but can't get pass the No Device Found problem. 

Been searching it but I can't find any. I can't understand the hex file burned on the MCU.
The 16u2 is merely acting as a usb to UART adapter. You can just as well use an ft232 or other serial adapter.

Of course the 16u2 needs firmware installing on it in order to function. That firmware is available (possibly bundled with the ide, or for download, not sure at the moment).