I read that quite a few time already, but because I don't know what an avrdude is it didn't mean much to me. I also assumed it was out of date because it only mentions 8u2, and if you read the Terminal entry line it doesn't point to the file that I'm talking about - it probably didn't exist when that was written -.
Doing some reading and it looks like Arduino got rid of avrdude, which is understandable because it way too hard for a beginner to understand.
More digging and I found you have to install WinAVR, but when I got to the Terminal none of the words in the flags mean anything to me so I don't know what they do or which ones I should use.
More reading and I only find old 2013 posts, but again no explanations of what the flags do just lines of text to enter in the Terminal.
Not knowing anything I pasted one in, but it doesn't understand it.
More reading and there is no comprehensive guide of flashing a 16u2 with avrdude from start to finish, so even if one of those lines of text sticks I don't know how the thing is physically connected to the PC in that example.
I found a GUI for avrdude, but the settings are abbreviated, so I don't know what they stand for, nor what they do.
As a beginner I don't have a chance with avrdude unless there is specific instructions from start to finish.
Latter on in the README it says FLIP compatibility anyway, and it just seams like that .hex is not compatible with that version of FLIP and needs to be fixed.
You can see in my video how easy FLIP is, so why not fix it so that file works.
Try FLIP and see if you get that 1 util byte, because that signifies a bug even before you flash the 16u2.