The error message acd0: FAILURE - unknown CMD (0x03) ILLEGAL REQUEST ASC=0x20 ascq = 0x00 indicates that there was a problem with a command sent to the acd0 device. The specific error code (ASC and ASCQ) indicates that the command was not recognized or supported by the device.
There are several potential causes for this error, including a faulty device, a driver issue, or a problem with the command itself. To troubleshoot the problem, you can try the following steps:
Check the hardware. Make sure that the acd0 device is properly connected and functioning. If necessary, try replacing the device with a known-good one to see if the problem persists.
Update the device driver. If the hardware is working properly, the problem may be with the driver. Check for updates to the driver and install them if available.
Check the command. If the hardware and driver are functioning correctly, the problem may be with the command that was sent to the device. Make sure that the command is valid and supported by the device.
If none of these steps resolve the issue, you may need to seek additional help from the manufacturer or from a qualified technician.