Software

ROM Bootloader

Enter ROM Bootloader Mode

Entering the bootloader is easy. Complete the following steps.

1. Make sure your microS2 is plugged into USB port to your computer using a data/sync cable. Charge-only cables will not work!
2. Check that you see the NeoPixel light on. So you know the board is powered, a prerequisite!
3. Press and hold the Boot button down. Don't let go of it yet!
4. Press and release the Reset button. You should have the Boot button pressed while you do this.
5. Now you can release the Boot button.
6. Check your computer for a new serial / COM port. On windows check the Device manager.

Run esptool and check connection

Once you have entered ROM bootloader mode, you can then use Espressif's esptool program to communicate with the chip!

• You will need to use the command line / Terminal to install and run esptool.
• You will also need to have pip and Python installed (any version!)
• Install the latest version using pip (you may be able to run pip without the 3 depending on your setup):

pip3 install --upgrade esptool

Then, you can run: esptool.py Make sure you are running esptool v3.0 or higher, which adds ESP32-S2 support

Run the following command, replacing the identifier after --port with the COMxx, /dev/cu.usbmodemxx or /dev/ttySxx you found above.

esptool.py --port COM88 chip_id

You should get a notice that it connected over that port and found an ESP32-S2.

You can now upload a binary file with the following command

esptool.py --port COM88 --after=no_reset write_flash 0x0 firmware.bin

don't forget to change the --port name to match, and the file name from firmware.bin to whatever the firmware file name is.

Once the data is verified, press the Reset button once more to launch the code you just programmed in!

UF2 Bootloader

microS2 uses TinyUF2 which makes flashing firmware and swapping between different platforms like Arduino and CircuitPython easy.

Using UF2 Bootloader

The UF2 bootloader presents itself as a USB drive to which the firmware can be copied to for flashing.

1. Press the BOOT button while the neopixel is purple during power-on to enter the UF2 bootloader.
2. The neopixel will turn red and then to a solid green indicating that you are in UF2 bootloader.
3. A drive with the label MICROS2BOOT will appear. Copy your firmware (in .uf2 format) to the drive.

Note: If you have a .bin file, you can convert it to .uf2 by following this guide.