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I need to modify the default latency on the FTDI drivers as it often gets reset when the device gets reconnected, but when I modify the default configuration file I get an error from windows saying that "The hash for the file is not present" and suggesting it has been tampered with.

It HAS been tampered with, but only the latency default value (usually 16). The FTDI APP Note (section 6.3) suggests it should be as simple as modifying that value, but it seems not!

Does anyone know if this can be done without paying for it to be digitally signed? The intended PCs for it to run on cannot have the digital signing check disabled due to security protocols, but if devices get unplugged and reconnected they will likely fall back to default latency and it will cause a lot of headaches...

Any help hugely appreciated guys.

Additional info:

  • Windows 10 x64 bit system
  • Using the drivers from FTDI Website
birdistheword99
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  • Parameters from the inf file go into registry during installation, right? so why not tweak them later here ```HKLM\SYSTEM\CurrentControlSet\Enum\FTDIBUS\{Device VID, PID and serial number}\0000\Device Parameters\LatencyTimer``` ? – Maxim Sagaydachny Feb 13 '21 at 06:13
  • @MaximSagaydachny Great idea, but unfortunately I won't be able to modify the registry keys on these machines I don't think, security restrictions – birdistheword99 Feb 13 '21 at 15:14
  • normally one can change the latency setting in the device manager and it should stay the same even after power cycling IF one connect it to the same USB port. Alternatively, can you use the D2XX instead of the VCP driver? Because there you can set the settings via function calls. – Christian B. Feb 13 '21 at 21:35
  • @ChristianB. what's the difference between the VCP and D2XX driver? And do you have any info on how to set it via the function call? – birdistheword99 Feb 14 '21 at 22:26
  • https://stackoverflow.com/questions/42573345/ftdi-differences-between-vcp-and-d2xx – Christian B. Feb 16 '21 at 21:59

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