I have done a lot of research on this (these forums included), and I think that this simply isn't possible, which is frustrating. Godamn microsoft and their stupid way of handling 8.1 I have a genuine Win 8 OEM key (purchased from Scan.co.uk, not extracted from a pre-installed OS or anything) I can install Win 8.1 Pro with a generic key, but when I am set-up, if I try to activate using my legit 8 key, it tells me it won't work with this version of windows. I also have an 8.1 Pro upgrade key, which doesn't work either. Is my only recourse to forever have to install 8, and then upgrade to 8.1 afterwards? I really wanted to have it all on a single installation disc. As I said I don't think it's possible, but if there's a method to activate it that I haven't found this is my last resort here. Thanks in advance.
Well, don't know whether this method will work but you can try, use the EI.cfg with the Windows 8.1 Pro Retail ISO and when asked for Key use the Key you purchased EI.cfg Contents Code: [EditionID] Professional [Channel] OEM [VL] 0 Even If this method doesn't work out, then you have one more option. - Install Windows 8.0 and activate the OS - Upgrade to Windows 8.1 - Backup the Activation tokens - Use My ToolKit to Integrate Pre-Activation Data and Key into the Windows 8.1 Pro ISO - Install the Windows 8.1
The EI.cfg works for both my Win 8.1 machines using a Win 8 Upgrade key with no issues at all (works better then installing Windows 8 ever did..)