I have exactly the same problem, requiring to run Hyper-V (for Docker mainly) on my HP Envy x360 Ryzen 2500u cpu. Enabling virtualisation in the bios and installing hyper v results in a boot failure, meaning recovery and fresh windows install :-(
The radeon driver that the hp support assistant installed was dated from October 2017 and refused to update it further... However searching around it seems that there is a newer driver from mid 2018. It took a while to work out how to install, but following the instructions given below I got it successfully updated.
It seems stable enough. However I've not yet been brave enough to enable hyper-v again (yet)! When I get around to doing a full machine backup (or someone else reports a success with this drive) I might try again...
Maybe the updated driver will fix hyper-v as someone used a March 2018 version which seemed to work:
I'll need to wait until next week before I test this though as I can't afford the time to do another install at the moment
And I can confirm that the driver available in the link above does resolve the issue, with hyper v running successfully.