.. _troubleshooting: Troubleshooting ############### I installed openFPGALoader but it says `command not found` when I try to launch it ================================================================================== 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 `_) ========================================================================================================================================== 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 `_) ================================================================================================================== 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 `_ or later). Cannot flash Tang Nano 9k (issue `#251 `_) =================================================================================================== 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 `_) ============================================================================================================================ 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 `_