Time it takes to transition from normal > DFU causing upload to fail 1st time

Having an issue whereby whenever i click “upload” in arduino with a board plugged in, the 1st time it gets to point where it is meant to transition the board to DFU, it does do that but seemingly too slow now for the followup flash process to work (just get the same kind of instant count of progress as you do with no board in)… i can hear windows transition (device unplug, plugin sound) and if i click upload a 2nd time it immediately flashes ok.

Just means i always have to press upload twice to get it to do it.
Is there a way to delay the time that the plugin (i assume that’s what is doing the work) to wait longer (even a second or two) before trying to upload


Are you giving your computer time to recognize the board before hitting upload? When you first plugin the board there is a period of time for the computer to recognize and connect. Try giving your computer a few seconds after you connect before hitting upload.

So, I don’t know what causes this on some computers, but so far, the solution has been to go change this 10 to 20 or 30:

To find this file on your computer, go to: Arduino → Preferences, then click the “preferences.txt” link near the bottom. In the window that opens up, go to packages/profezzorn/hardware/stm32l4/<VERSION>/tools/windows, and that’s where you’ll find the file.

The problem, whatever it is, seems to be fairly rare, which is why I haven’t updated the timeout for everybody yet.

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Yeah. Board is recognised in Arduino. Plus the time it takes to compile is another 10s at least. It’s just the moment Arduino switches the board into dfu it then seems to take a couple seconds so it misses the first run through