Connect via USB (ensure the CH340 driver is installed) and select Arduino Nano (ATmega328P) as the board. How to Upgrade Firmware on the ATS-20+ Radio (Correct way)

If you still have the stock firmware on your ATS20, It turns a $50 AliExpress toy into a genuinely usable portable HF receiver.

"Come on," Elias whispered, his breath fogging in the cold garage. He knew the risks of messing with the Arduino-based heart of the device, but the lure of a more efficient spectrum display was too strong.

Have you flashed your ATS20? Share your experience and favorite firmware build in the comments below.