mgsecord62 wrote:I don't know how you have the rotary encoder connected, but my guess is that GPIO15 (D8) is not low when you are trying to download until you disconnect the 3.3 volts.
Thank you and you are correct. I replied to my own post before noticing you'd responded but that was exactly the issue. I sorted this late last night and didn't have time to post before I had to go to bed.