OpenOCD Troubleshooting: Device Not Opened (Linux)

On startup you see an error message indicating that OpenOCD cannot find the device. If your build of OpenOCD uses the libftdi driver library, the error message reads:
Error: unable to open ftdi device: device not opened

Device Not Opened error with libftd2xx

With OpenOCD 0.4.0 this error appears as:

Error: unable to open ftdi device: 3

Try the following to correct the issue.

 

Manually Unload the FTDI_SIO Driver

OpenOCD should unload the ftdi_sio kernel module automatically on startup. If it fails, you will see the “device not opened” error. You can correct this by manually unloading the module with this command:

sudo rmmod ftdi_sio

You should see no text output, and the command prompt should appear again immediately. You should now be able to start OpenOCD successfully.

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