I have everything working. ISO Lable is IR3_CPRA_X64FRER_en-US_DV9.iso. Install does not ask for serial number. Installation is in progress.
Hopefully they don't change the crypto key for the preview build updates, this way we can extract full ISO's to have on hand for each new build
In the windowsupdate.log it downloads both a provisioned esd file with the Background Int service and a windowssetupbox.exe They get put in your softwaredistribution\download folder. We can try working with this and see if plugging some retail keys in might help. *edit: hmm actually it's one of those exe files that runs with arguments. It doesn't have a front-end like the downloaded one.
these newer esd files decrypt just fine with the default crypto id in the esddecrypt.exe they all have a trailing sha1 hash. I'd link the direct downloads but I believe they are provisioned downloads since they give the download server some arguments. We could probably get all or most of the retail channel versions of these esd files, but the store doesn't allow esd downloads for the vl versions. Since it has a trailing sha1 now, it's not as simple as re-naming the file in the download url and downloading different versions.
They always had trailing sha1, and they all require Store authentication time to wipe Windows 10 of the VM