Amazing! Albert, this is a fantastic effort, thank you!
Following your steps, I managed to get my Seeeduino Mega reprogrammed and running using Avrdude command prompt.
It’s worth noting that I did have one problem. At step 6, there was an error setting the efuse
But I kept following the instructions, and on exit AvrDude asked me:
I chose ‘no’ and I was able to reprogram the 1280 hex file. All is working perfectly.
So thank you very much Albert.
Now I just need to get Firmata working properly on it…