[Libusbx-devel] libusb_control_transfer() stalls

[Markus <li...@ne...>]

Hi,

I'd like to replace a vendor tool for firmware download
to a developement board by using libusbx.

As of now, I can read and write memory by using vendor request
control transfers. According to the manufacturer this is the way 
to go for firmware dump and download.

wValue (LSW) and wIndex (MSW) make up the address offset to write 
the data to within device memory.

In both cases (r/w), the maximum value for wValue is 0x4000, after
that libusb_control_transfer() returns pipe errors. As it is
possible with the original tool to write beyond this address, I
suspect it's not the device that produces the stall.

Do you see a possibility that it originates from libusbx or
should I concentrate on the driver (which is WinUSB installed by
the latest libusbK driver wizard)?

As I don't have any known-good device where I could meaningfully
test a control transfer with wValue > 0x4000, I'd also be happy 
for any hint towards how to reproduce this behaviour.

Thanks in advance,
/Markus