Solved How to update Windows 8.1 setup USB with Update 1

I created a setup USB with the ISO of Win 8.1 and its now out of date after the Spring Update 1. With XP you could slip stream service packs and updates. Does anyone know how I can incorporate Update 1 into Win 8.1 Setup USB stick?

Tim

Download a new ISO of 8.1, it will include update 1.

Thanks but where is the latest official ISO?

edit:

Create installation media for Windows 8.1

Take a look at this post: link

Thanks looking now, wonder if my custom ei.cfg will work with this version as I only have a win 8 key?

See here: http://www.eightforums.com/installation-setup/33164-how-download-windows-8-1-iso.html

and later i n the same thread here: http://www.eightforums.com/installation-setup/33164-how-download-windows-8-1-iso-9.html#post295128

Many thanks to all who contributed to this thread. I have access to the MSDN 8.1 ISO download list but cant download due to lack of subscription so did a search for the english british version on google and got it and checked the hash from the MSDN list and it matches. So I now have an installation USB stick with custom ei.cfg and default keys if needed so I can load and activate Win 8.1 Update 1.