The story of the firmware is one of a community-driven transformation, where independent developers turned a simple "toy" radio into a versatile tool for amateur radio enthusiasts. The Evolution of the Firmware The Original (V1.1.5): Most ATS-20 units ship with stock firmware based on the PU2CLR Si4735 library
The (often called the ATS-20+ ) is a portable all-band radio based on the Si4732/Si4735 chip and an Arduino-compatible microcontroller. Updating the firmware is a popular way to add features like SSB (Single Side Band) support, RDS, and better battery monitoring. Preparation & Required Tools Before starting, ensure you have the following:
Some custom builds even add using just the existing LCD and clever timing tricks.