I wouldn’t start replacing components yet. You might want to wait until you re-flash it. I’m pretty sure your LM386 was good because it made noise when you shorted some pins together. The 6N138 definitely won’t be causing the problem.
I just talked to Glen and he thought he sent Koma a usbtiny for this very purpose…but maybe he was mistaken. We’ll send them one…so you can use it there. You can order your own, but you probably don’t need to. We’ll try to get it in the mail tomorrow.
Unfortunately, at this time our ZDL Updater software is for PC only. Sorry.
-Brach