.. _faq-index:

Frequently Asked Questions
==========================

Documentation Help
------------------

General help regarding this documentation can be found in :ref:`docs-help`.

General Questions
------------------

Connecting TTL Terminal
~~~~~~~~~~~~~~~~~~~~~~~

How to connect a terminal to your module see :ref:`ttl-converter-connection`.

Enabling USB Bootmode
~~~~~~~~~~~~~~~~~~~~~

For instructions on how to enable the USB (Serial Downloader) boot
mode on your module, please refer to: :ref:`enabling-bootmode`.

Select Function of USBOTG port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The function of the USBOTG port can be selected via the U-Boot environment variable ``otg_mode``.

.. list-table::
   :header-rows: 1

   * - Variable setting

     - USB port function

   * - host

     - USB host port (for connecting USB devices like memory sticks or
       ethernet/serial converters)

   * - peripheral

       device

     - USB device port (for using the module as a USB gadget)

   * - none (or empty)

     - USBOTG port deactivated

The setting of this variable does not affect the Serial Downloader mode.

Example:

.. prompt::
   :prompts: U-Boot >

   setenv otg_mode host
   saveenv

Updating Single Files
~~~~~~~~~~~~~~~~~~~~~

How to update single or multiple files on our modules without re-flashing the whole module see :ref:`update-files`.

UUU on Windows 7
~~~~~~~~~~~~~~~~~

If you want to run **uuu** on a Windows 7 host have a look at :ref:`uuu-win7`.

Troubleshooting
---------------

UUU USB Failures
~~~~~~~~~~~~~~~~

If you're experiencing USB connection failures with **uuu** see :ref:`uuu-usb-failures`.

Compile Errors on Modern Kernel
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you have compile errors on a Host-System with modern Kernel (>=5.4) see :ref:`linux-host-modern-kernel`.

Requested init /linuxrc failed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Use ``init=/sbin/init`` on the Kernel Commandline.