If plugging your MONSTER M4SK board into a computer over USB and it does not appear as a small flash drive named CIRCUITPY, it’s usually one of three reasons:

  • Verify that you’re using a USB “charge and sync” cable, not a charge only cable.
  • The first batch of MONSTER M4SK boards did not have the flash filesystem initialized…we’ll cover that below.
  • Something happened…maybe static, maybe a bug in the software…and corrupted the flash drive contents.

If you do see the CIRCUITPY flash drive, everything’s good and you can skip ahead to the next page.

Creating the SPI Flash Filesystem

If the CIRCUITPY drive does not appear, this just involves temporarily installing a version of CircuitPython. The eye code isn’t written in CircuitPython, we’ll just use it here to get the flash initialized!

Download that .UF2 file here:

Connect MONSTER M4SK to your computer with a USB cable, set the power switch to the ON position and double-tap the reset button to enter bootloader mode.

After a moment, a drive called MASKM4BOOT should appear.

I’m not seeing the MASKM4BOOT drive!

Things to check:

  • Confirm the power switch is in the ON position.
  • Double-tap the reset button again. The red LED on the back should do a slow “breathing” cycle. If not, try again.
  • Make sure you’re using a good USB “charge and sync” cable, NOT a “charge only” cable.

Drag the CircuitPython .UF2 file to this drive and wait a few seconds.

After CircuitPython installs, and with the MONSTER M4SK board connected over USB, it should appear on your computer as an 8 MB flash drive called CIRCUITPY.

In rare situations the flash memory might need a complete erasing, before even setting up the flash filesystem. The Troubleshooting page of this guide includes a utility for this. Once erased, you can then start again with the filesystem setup as described above.

Initializing the filesystem is a one-time operation. You should not need to repeat this process, unless the flash drive contents somehow get corrupted.

This guide was first published on Aug 20, 2019. It was last updated on Sep 18, 2023.

This page (Flash Filesystem) was last updated on Aug 19, 2019.

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