Hi HunterReed,
Miracast is a built-in feature in a Windows 10 device, to be able to update its driver you may follow these steps:
- Right-click on the Windows icon on the bottom left of your screen.
- Choose Device Manager.
- Once the Device Manager opens up, look for Display adapter.
- Expand it by clicking the arrow (>) pointing to the right.
- Right click on your HD Graphics driver and choose Update Driver Software.
Let us know the result for us to help you further.
Regards.