The 3-Second Brick (And How an AI Saved My Evening)

During the development of my Sourdough sensor project, I managed to flash some bad firmware to my devboard.

The code didn’t crash, but it went into a deep sleep after just three seconds. Because of that, the serial port wouldn’t stay active long enough for me to flash a newer firmware version.

It wasn’t a fatal issue, but it was going to be a hassle to fix—and not what I wanted to deal with during an evening hobby session. So, I just picked up another Wemos D1 mini I had lying around, flashed it, and moved on.

Fast forward to today.

I got back to the project because I needed a second devboard to test my home-brewed OTA system.

I remembered the semi-bricked board and, without expecting much, asked an LLM to write a quick script to watch the specific /dev/... port and attempt to flash a basic Arduino LED blink code the moment the board responded.

It worked on the second attempt. I didn’t even have to adjust the prompting, check the firmware code, or look up flasher arguments.

By the time I finished typing this post, it had also completed flashing the actual OTA firmware I wanted to test.

What a time to live in—both good and scary.