How to Flash Firmware
Flashing firmware writes new program code to your microcontroller flash memory.
ESP32 / ESP8266 (esptool)
pip install esptool
esptool.py --port /dev/ttyUSB0 --baud 921600 write_flash 0x0 firmware.bin
Hold BOOT, press RESET, release BOOT to enter download mode.
Arduino (avrdude)
avrdude -c arduino -p atmega328p -P COM3 -b 115200 -U flash:w:firmware.hex:i
Or just: Arduino IDE → Sketch → Upload.
Raspberry Pi Pico (RP2040)
- Hold BOOTSEL while plugging in USB
- Drag .uf2 file onto the RPI-RP2 drive
- Auto-reboots with new firmware
Meshtastic (Web Flasher)
Go to flasher.meshtastic.org, select device, click Flash.
Troubleshooting
| Symptom | Fix |
|---|---|
| Permission denied | sudo usermod -a -G dialout $USER |
| Chip not detected | Enter bootloader mode (BOOT + RESET) |
| Bad USB cable | Use data-capable cable, not charge-only |