Last time I loaded ground control 1.26 on hundreds of Mega2560 boards one by one and it was super boring took me about 2 or 3 days on and off.
I’m guessing that is the only way, but thought the community might know a more efficient method?.
edited to add:
I found this post below, but do not understand what the heck he is saying? Sounds like he made a custom wiring harness that plugged into many boards at once and then connected one via usb to the pc and it programmed the entire batch at once??
SOLVED… Frist thank you all for you input I found it to be extremely invaluable. It was a simple fix but I found out how to upload a sketch to many Arduino’s at the same time. This was key!!! - You connect all the GRN in parallel (from the FTDI - the DTR connection and the Arduino’s GRN) , the TX from the master serial (in this case my FTDI) connects to all the RX on the slave Arduino’s in parallel and the GRD on all connected together as well in parallel. The only down side is that you can’t receive a verify from the uploaded. But it’s not needed in this case. Again thank you for the help.