I had followed your instructions and performed an update to the BIOS and updates through the HP Support Assistant, but the pen worked properly for a split-second and went back to not performing any functions.
This sounds like hardware related issue with the HP Pen. Hence, I would request you to contact our Support and our Support Engineers should be able to sort this out. HP Support can be reached by clicking on the following link: www.hp.com/contacthp/
Please feel free to contact us here anytime you need any further assistance. Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".