In-Place Windows 7 RC downgrade to Windows 7 Home Premium

a few months ago, i posted a link to a hack that revealed how to do an in-place “upgrade” (although it’s really a downgrade) from Windows 7 RC-1 to a lesser version of Windows 7.  as the nag alerts saying i need to backup my stuff and reinstall have started cropping up, i decided to finally put the copies of Windows 7 i actually purchased to use.  but i knew i was going to be in for some issues.

click here to skip the narrative and go straight to the fix.

see, what i did — which made perfect sense at the time — was i took advantage of the limited-time, special pre-order discounts that were available towards the end of the official testing period, grabbing two copies of Windows 7 Home Premium upgrade for $50 each.  i figured, someone, somewhere, would figure out how to hack them to just do an upgrade from the RC.  they figured out how to hack the beta to the RC when you weren’t supposed to be able to do that…

the problem of course (which didn’t apply to the beta → RC upgrade), is that Home Premium is a different version of Windows than RC, which uses Ultimate.  and therein lies the issue — an issue i realized would be a problem when i tried the upgrade sometime in december (before i found the hack) and it was giving me this message:

when i went to do the upgrade using the method i linked to after christmas, i still got the same message.  i didn’t get it.  yes, the hack was a pretty stupid hack, just changing a couple registry values from “Ultimate” to whatever version of Windows was less than what you were trying to install, but still, supposedly people had done it with success.

it wasn’t until i found this hack — which is based on that one — that i was able to figure out a way to get it to work.

so the original hack goes like this: open regedit, and go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion and change the values for EditionID and ProductName.  The assumption is that you could change them to whatever you want, just name it the name of the operating system.  so you’d go from “Ultimate” to “Home Premium.”  the problem, of course, is that this didn’t work.  and from what i could tell in the comments for that post, it didn’t work for a lot of other people trying to downgrade to home premium.

the difference in this other hack i found, first of all, is in how the edition is named — e.g. it’s important that you use the exact name that the edition identifies itself as on the DVD, which he displays in a graphic:

so, that helped, but it still didn’t work.  i used “HOMEBASIC” and “Windows 7 HOMEBASIC” in the correct keys and still got the same message saying i can’t upgrade from Ultimate to Home Premium.

really, Microsoft?  i finally decide to spend money on your operating system and — because of a loophole in your installation process — you’re still going to try to either suck even more money out of me or force me to find a pirated copy anyway?  i started warming up my demonoid searches…

but then i notice that the post indicates that the registry values you enter need to match the version you are installing.  but that can’t be right…surely changing the values from “Ultimate” to “HOMEPREMIUM’ aren’t going to work on a Home Premium install, are they?  it works like the cversion.ini hack used to upgrade from beta to RC — you just need to make it something less than the current version…

i tried it and, whadayaknow, i saw a new screen:

so i knew i was in pretty good shape when i saw the installation actually start working.  i was a little nervous, however, when the install hung at 20% on “Gathering files, settings, and programs”.  i stopped and restarted it when i didn’t see it changing at all, and it hung again at 20%.  this time i left it alone and went away from the computer.  a while later i came back and saw it had moved to 88%, and it was fine from there.

note:  i will say that at some point the computer rebooted and brought up a screen about how the repair wizard couldn’t fix the startup error.  i closed that screen, the pc shut down, but then started windows for the first time fine after that.  it’s been working with no issues since, so i’m calling it a fluke for now.

after that, it booted up fine and asked for my product id (which, of course, i have), and has been working like a charm ever since with a retail version of windows 7 home premium.

so, once again, here’s how to downgrade from Windows 7 RC-1 (Ultimate) to Windows 7 Home Premium
(note:  presumably this would work with other versions but as i have not tested it on any other version, I can’t vouch for it personally, although the original post i used as reference indicated it would work for Home Professional as well)

1 – open the registry editor by going to Start > Run > regedit

2 – navigate to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ WindowsNT \ CurrentVersion

3 – double click EditionID to open it and change the value from “Ultimate” to “HOMEPREMIUM”

4 – double click ProductName to open it and change the value from “Windows 7 Ultimate” to “Windows 7 HOMEPREMIUM”

you’re done.  it works without a reboot.  you should be able to just start your installation.

also note: this is still using the method that changes the cversion.ini file on the DVD image, so you’ll still need to do that first.

okay, ready, break. you’ve got about 9 days left before your computer starts shutting down.  if you waited this long to install the retail version, wait no longer, do it now.

2 Replies to “In-Place Windows 7 RC downgrade to Windows 7 Home Premium”

    1. yeah, i'm actually pretty impressed that such a simple tweak would work. i will say, however, that on the two machines i did this on, i had some minor driver issues. on one, which has an onboard and a pci-e video card (which are both within 1 series of each other, one's an nvidia geforce 7-series and the one i actually use is an nvidia geforce 8-series), windows sort of freaked out with the two video drivers and after an update, would do a constant reboot loop. i eventually nailed it down to the video driver after uninstalling the drivers in safe mode and booting up — as soon as i installed (or rather, let windows auto-install) the drivers, it caused the same issue. even the current nvidia drivers didn't solve the problem. so the ultimate fix was disabling the onboard video card i wasn't using in device manager.

      my other machine had a similar problem with the onboard network adapter, and even after i tried adding in an actual card, i still couldn't get connected. what ended up being the issue for that was that it was defaulting to an older driver, version 6.0, but when i said "have disk" and then "show me a list of installed drivers" there was a 6.20 version available, and it worked perfectly after i installed that.

      the moral here is that there may still be some issues after the up/downgrade, but most of them are workable if your enough of a geek to be able to perform the hack in the first place.

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