If you are still able to boot the RPi3B, how about re-tasking it to be an alternative desktop PC or a media player.
at least you'll still have some good use for it.
I rewired everything according to gordon77's link and now everything works OK.Z80 Refugee wrote: You can't kill an I/O pin just by controlling a different one, there has to have been an incorrect physical connection.
Now, if I might digress, I don't understand this WiringPi numbering business. For my Forth tutorial I use WiringPi for the GPIO control, and I had no trouble using pin assignments as per the GPIO (BCM) numbering. If the numbering had been as per that link in gordon77's post, it wouldn't have worked. Somebody please explain.
Beginners Guide to Wiring Things to the GPIO
Installing and Using Forth on the RPi