Most times the issue is a bad firmware usb thumb drive mounted on the main board. They are available from hp parts for 25.00 which is the way I would first go since it is a lot cheaper then the main board which comes with the same drive. The part number is CQ890-67105.
Just go to the link below and put the part number in to order.
https://parts.hp.com/hpparts/Default.aspx?mscssid=
Do a google search for the service manual and you have to remove the main pca board and on the back side is where the drive is mounted. If the drive does not work, then the complete main pca will have to be replaced as new pca's come with the drive all ready installed.