.. _troubleshooting:

Troubleshooting
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I installed openFPGALoader but it says `command not found` when I try to launch it
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The correct spelling of the program is *openFPGALoader* with FPGA and the "L" of "Loader" in uppercase.
Ensure the spelling of the program is correct.

Gowin device could not communicate since last bitstream flashed. (issue `#206 <https://github.com/trabucayre/openFPGALoader/issues/206>`_)
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Gowin's FPGA may fails to be detected if **JTAGSEL_N** (pin 08 for *GW1N-4K*) is used as a GPIO.
To recover you have to pull down this pin (before power up) to recover JTAG interface (*UG292 - JTAGSELL_N section*).

JTAG init failed
================

Avoid using USB hubs and connect it directly to your PC USB port.


Tang Primer 20k program slow and stucked (issue `#250 <https://github.com/trabucayre/openFPGALoader/issues/250>`_)
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Check your openFPGALoader version:

.. code:: bash

    openFPGALoader -V

If it is older than release then v0.9.0, install the most recent version (from commit `f5b89bff68a5e2147404a895c075773884077438 <https://github.com/trabucayre/openFPGALoader/commit/fe259fb78d185b3113661d04cd7efa9ae0232425>`_ or later).

Cannot flash Tang Nano 20k (issue `#251 <https://github.com/trabucayre/openFPGALoader/issues/511>`_)
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Some firmware version cannot be flashed on Linux-based systems. Version 2024122312 is such an example. It seems this version was not published on the `SiPeed website <https://api.dl.sipeed.com/TANG/Debugger/onboard/BL616/>`_, however some boards sold have this firmware.

The cause of the problem is the debugger on the Tang Nano, specifically the firmware of this debugger. This firmware can be easily updated by following `these <https://wiki.sipeed.com/hardware/en/tang/common-doc/update_debugger.html>`_ steps.

Cannot flash Tang Nano 9k (issue `#251 <https://github.com/trabucayre/openFPGALoader/issues/251>`_)
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This is a device issue, erase its Embedded Flash using Official GoWin Programmer (preferentially in Windows) and SRAM too, then you can use openFPGALoader again.

Unable to open FTDI device: -4 (usb_open() failed) (issue `#245 <https://github.com/trabucayre/openFPGALoader/issues/245>`_)
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Edit your `/etc/udev/rules.d/99-ftdi.rules` file exchanging your programming device permissions.

For more information, check the udev section from `this guide <install.rst>`_