We noticed that our firmware upgrade for device that uses RT685 in ISP mode fails to work on a certain PC. It works on many others. So after some investigation discovered that the Windows "System" process (PID 4) is opening all devices including the ISP device on its own. And when "System" has the device opened, BLHOST.EXE cannot open it, so firmware upgrade fails.
Further investigation reveals that the BLHOST.EXE uses the usblibsio.lib which has hidapi library code. Note that the latest hidapi library opens devices with following share modes: FILE_SHARE_READ | FILE_SHARE_WRITE. But the usblibsio.lib opens devices with this share mode: FILE_SHARE_READ. Why hasn't usblibsio.lib been updated to the latest hidapi code?
What happens is the System process opens the device in the FILE_SHARE_READ | FILE_SHARE_WRITE share mode. And then BLHOST.EXE attempts to open it, but it does not have FILE_SHARE_WRITE share mode, so it fails.
I would think that more people would be having this problem, but don't see anything on the boards about it.
The PC that is having the problem has following operating system version:
Any help on this is appreciated. Thanks.
This seems to be a machine specific issue, rather than an RT one.
Have you tried using a different computer or a different OS to use with your RT685? If no, could you do so and share your results?