Solved 8.1 pro volume license key fails when installing from USB

I have a Vostro laptop running Win 7 pro x86. I want to upgrade it to Win 8.1 pro x64 and have a volume license key. The optical drive on the laptop is broken so I need to install from a USB stick. I created a bootable USB drive from here:
Create installation media for Windows 8.1 - Windows Help

The laptop boots from the stick, but when I input my license key, a message pops up saying it can't verify the product key.... please check your installation media. I have the laptop connected via ethernet cable, so I don't believe it's a connection issue.

Is installing from a USB stick not supported for a volume license key?

https://technet.microsoft.com/en-us/library/hh824952.aspx

It appears you need to use volume license software and not OEM/Retail software

Windows 8.1 Pro Volume License with Update (x64) - MSDN ISO [November 2014 Rollup]

File Name: en_windows_8.1_pro_vl_with_update_x64_dvd_6050880.iso
Languages: English
SHA1: 962A1D890987B5877469433928B8C8B8A3E945CD

The last time I messed around with VL, I could swap keys on retail media... things may have changed subsequently - need to do a quick VM test. Assume it's a Professional Volume:MAK key.

Yes, I have the Win8.1 x64 ISO file. I tried the Windows USB/DVD download tool:
Windows USB/DVD Download Tool - Microsoft Store

but it failed with an error message something like:
unable to run bootsect to make the usb bootable

This on both a Win 8.1 pro x64 and a Win 7pro x64 computer.

Now I'm trying a tool called Rufus: (I found over in Sevenforums)
Windows 7 USB/DVD Tool - "unable to run bootsect" - Windows 7 Help Forums
https://rufus.akeo.ie/

It created the bootable USB drive without issue. I'll find out shortly if it works.

Edit: Plugged in the USB drive, rebooted the laptop and chose the USB drive to boot from and it works great!

Good to hear - FYI: seems the retail media doesn't like MAK keys - they accept GVLK's though.