Tormod Volden

Thanks for a good and detailed bug report. Unfortunately, the LIBUSB_ERROR_NOT_FOUND appearing together with "found on devnum XX" means that the DFU device was available for a short time but then disappeared. It is probably not staying long enough in DFU mode. This is a problem in the device bootloader, or the program (IDE) that puts it into DFU mode. There is not much dfu-util can do about it.

Or .hex file.

It seems that you are programming an .elf file directly onto the device. You should extract a binary file from the ELF file and use that instead.

https://github.com/mchehab/zbar/issues/212

Interesting, thanks! At a first view, this seems to make sense. It is limited to 65535-2 blocks though, but that can be dealt with if necessary. How much is the gain that you are seeing?

The warning that you put in the title is just a warning. It has nothing to do with "No DFU capable USB device available". Did you at all read https://sourceforge.net/p/dfu-util/tickets/new/ ?

Thank you Here at the dfu-util bug tracker we only deal with dfu-util itself, not the Arduino IDE. Arduino bundles their own modified version of dfu-util. This is the the problem that dfu-util sees (exit status 74 is just a code for this): |dfu-util: No DFU capable USB device available| So the Arduino IDE hasn't successfully made a DFU device available for dfu-util.

symbol lookup error after new install