Windows ambiguous error for busy serial.

[beikeland]

This is the output I get from an free serial port with no target; as expected.

C:\Users\bearer>"%programfiles(x86)%\BOSSA\bossac" --port=COM3 -d -e -w -v -b  Downloads\Duet3Firmware_MB6HC.bin -R
Send auto-baud
Set binary mode
No device found on COM3

If the same serial port is busy, the error message still suggest the problem is with the target and not specifically the serial port.

C:\Users\bearer>"%programfiles(x86)%\BOSSA\bossac" --port=COM3 -d -e -w -v -b  Downloads\Duet3Firmware_MB6HC.bin -R
No device found on COM3

Could be clearer by stating "Failed to open COM3" or something to that effect.