Windows 8.1 Pro wants to upgrade to 10 Home

I recently bought a new Acer laptop, that had Windows 10 Home preinstalled. Since I still had a Windows 8 Pro key, I wanted to upgrade that to 10 Pro.

What I did so far:

• Install Windows 8.1 using a generic key (as the installer didn't accept the Win8 key)




• Enter the Windows 8 key and activate license




• Using MediaCreationTool I created a bootable Windows 10 USB drive




• As suggested here I created PID.txt inside the Sources folder, that contains my original Windows 8 key I used to activate 8.1




• When booting from the USB drive and choosing to upgrade Windows, I get the following notice:

  
  

  Compatibility report

  
  

  The computer started using WIndows installation media. Remove the installation media and restart your computer so that Windows starts normally. Then, insert the installation media and restart the upgrade.




• However, when restarting the upgrade after booting Windows, it wants to install Windows 10 Home

So what else can I try, to upgrade to 10 Pro?