Well, if the list of what you did "in the end" is correct, then you did not follow the directions you linked to.
Also, unless you are trying to follow directions from different locations or posts, there are no 'loose ends'. It seems very likely you are mixing directions taken from more places than the single source you linked to.
Please describe: "doesn't want to install"
We can not diagnose: "broke"
Have never heard of such a banner, give us a screenshot (two fingers, touch diagonally opposite corners of the screen).
How are you entering diags mode?
That normally can not be done unless you have done something you have not mentioned.
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