The following shows a typical run through installing and setting things up on Linux.

Install libusb and libudev

Run the following to install required libraries:

and answer Y to the prompt. This should install libusb and libudev.

Setup udev rules

Use a text editor to create and edit the file /etc/udev/rules.d/99-mcp2221.rules and add the following contents.

Here we use nano, so run:

like this:

and add the contents from above:

and then press CTRL-X and Y to save and exit.

The settings will take effect the next time you plug in the MCP2221.

Install hidapi

To install hidapi, run:

Remove Native MCP2221 Driver

Starting with Linux Kernel 5.7, a native MCP2221 driver (hid_mcp2221) is included with the installation. This will interfere with the HID generic driver (hid_generic) used by Blinka.  The native driver can be temporarily removed (disabled) with:

To prevent the driver from loading again at boot or when reinserting the MCP2221, update the kernel module blacklist configuration. Add this line to /etc/modprobe.d/blacklist.conf

Then run the following command to also update the configuration in initramfs (details):

Reboot the system.

Install Blinka

To install Blinka and its dependencies, run:

Set environment variable

We need to manually signal to Blinka that we have a MCP2221 attached. To do this, we set the environment variable BLINKA_MCP2221. The value doesn't matter, just use 1:

Run the sanity check.

Now move on to the Post Install Checks section and run the commands there to make sure everything is installed correctly.