Troubleshooting DFU bootloader USB connections.

[dlech]

This page applies to SPIKE Prime, SPIKE Essential and MINDSTORMS Robot Inventor hubs only. These hubs use a DFU bootloader via USB for firmware updates.

To place the hub in bootloader mode:

1. Disconnect the USB cable.
2. Turn off the hub.
3. Press and hold the Bluetooth button (or power button if there is no Bluetooth button).
4. Connect the USB cable (to both the hub and your computer).
5. Wait for the Bluetooth light to start blinking pink-green-blue-off (or wait for the status light to start blinking light purple if there is no Bluetooth light).
6. Release the button.

If the light does not come on after 5 seconds, try disconnecting the USB cable and removing the battery. Then replace the battery and try the steps again.

Once the hub is in this mode, your computer should recognize it as a Lego Group LEGO Technic Large Hub in DFU Mode (it will say Small instead of Large for the Essential hub).

Basic operating system checks and configuration

Depending on your operating system, you may need to perform some manual configuration before you can use your hub. This configuration generally only needs to be done once per computer.

Windows

Confirm that the device is connected

• Open the Device Manager (there are a number of ways to do this, for example, right-click the start menu and select Device Manager):

  

• Search for Lego Group LEGO Technic Large Hub in DFU Mode (or Small instead of Large for the Essential hub).

  

• If the hub has a warning sign, then it has no drivers installed and won't appear in any applications. If this is the case, you can manually install the driver.

  

macOS

Confirm that device is connected

• Open the  menu and select About this Mac.
• Click the System report... button.
• Select USB under Hardware.

There are no special drivers or configuration required for macOS.

Linux

Confirm that device is connected

You can confirm that the computer sees the device by running lsusb in a terminal window. You should see a line like:

...
Bus 005 Device 030: ID 0694:0008 Lego Group LEGO Technic Large Hub in DFU Mode
...

However, just because you can see the device listed here, doesn't mean you can use it. Permissions need to be properly configured as well. See the udev rules section below.

Pybricks Code

If your hub does not appear in Pybricks Code when you try to flash the firmware, first go through the checks above to make sure that there is not a problem an the operating system level.

In the web browser, you can open pages to chrome://usb-internals/ and chrome://device-log/ to get more information.

[dlech]

Manually installing USB driver in Windows

As describe above, if you see a warning sign in the Device Manager next to Lego Group LEGO Technic Large Hub in DFU Mode like this, then you need to manually install the USB driver for this device.

1. Double-click the device to open the Properties page.

   

2. Go to the Drivers tab and click the Update Driver button.

   

3. Select Browse my computer for drivers.

   

4. Select Let me pick from a list of available drivers on my computer.

   

5. Select Universal Serial Bus devices and then click Next.

   

6. Select WinUsb Device under Manufacturer and again under Model then click Next.

   

7. Accept the warning by clicking Yes (we have verified that the driver is compatible).

   

8. The driver should successfully install and you can click Close.

   

[dlech]

Adding udev rules on Linux

By default, Linux does not allow the use of unknown USB devices, so you need to add udev rules for your hubs. Pybricks provides a couple of ways to do this.

If you are using an Ubuntu-based Linux distro, you can install the pbrick-rules package from the Pybricks PPA. This method has the advantage of automatic updates.

sudo add-apt-repository --update ppa:pybricks/ppa
sudo apt install pbrick-rules

You can alternately install the rules using the pybricksdev command line tool:

pipx run pybricksdev udev | sudo tee /etc/udev/rules.d/99-pybricksdev.rules

If neither of these options is suitable, you can manually copy this file to /etc/udev/rules.d/99-pybricksdev.rules.

After installing the udev rules, disconnect any affected devices and plug them back in.

If this doesn't seem to work, try rebooting.