Thanks for the Win 10 FAQ link.
This part was of particular interest to me in the FAQ:
Can I dual boot the free upgrade of Windows 10 with my previous version of the operating system?
No. Upgrading to Windows 10 doesn't free up your previous license, so you cannot install your previous version on another machine or in a dual-boot configuration. The upgrade requires installing Windows 10 on top of a valid version of Windows 7 or Windows 8 installation to continue with the upgrade process.
Of note to me is there's no mention of using separate HDD's for running the user's previous Win OS and the upgraded Win 10 OS using Cloned or Image-restored HDD paths.
I didn't put much weight on this being omitted since as most here know, Cloning and Imaging is often not mentioned as a PC rollback path in articles similar to this FAQ article.
I started a thread over at the Win 10 Forums about this issue. I got some interesting replies. Here's the thread link:
Rollback via Cloned HDD or Image Restore after 30 days - Experiences?
Five of my personal Win 10 hurdles appear to have been cleared about the upgrade. I haven't decided about upgrading during the 1-year free time period yet as I'm also interested in the privacy angle regarding Win 10 but these 5 points might have been virtual deal breakers for me but seem to have been answered favorably regarding my possible decision to upgrade.
- Rollback via Clone or full-HDD Image restoration will work, after the 30-day time period expires, according to the Win 10 members that posted in the thread.
As Union_Thug mentioned in his post, the 30-day period references the "Windows Old" rollback path and not reverting via a Cloned (or Image-restored) HDD.
- Previous Win OS license/keys: According to the Win 10 members, the previous Win 7 / 8.1 keys aren't invalidated after the Win 10 upgrade.
- Inbedded Keys in the Firmware (MoBo's): Here's a post from the thread replying to my question about this:
The future-upgraded Win 10 Key won't be stored in firmware on ANY motherboard. All Windows 10 upgrades from Windows 7/8/8.1 get the same product keys (depending on the version; home, pro, etc.). No version of Windows has ever stored Product Keys to motherboard firmware. Manufacturers with OEM licenses started storing product keys in bios beginning with Windows 8 - but the Windows operating system never has, and still doesn't.
- Win 10 and replacing the OS HDD: According to the Win 10 forum members in that thread, there isn't anything unique about Win 10 and HDD replacements as compared to previous Win OS versions.
I'd read some mention in this forum about it. If this had been an issue, it would not fly with me as I'm a HDD backup nerd and have been Cloning periodically (with occasional Imaging) for about 4 years with almost no issues. I encountered 2 Cloning failures of about 125 but discovered the reason for the 2 errors. The failure reason was interesting but not on topic here.
Every Win PC user needs the option of replacing the OS HDD at any time and without restrictions, in my view. The reasons are numerous and are old news for members here; HDD failures, rollback from malicious presences, user errors, bad downloads, verifying Cloned or Image-restored HDD's, etc.
- Running the previous Win version and Win 10 using independent HDD's on the same PC:
Several Win 10 Forum members there have been running their previous Win OS and Win 10, using separate HDD's (only 1 OS HDD installed in the PC at a time), without issue during the Win 10 beta build testing period.
According to one member's post (see post #4 in the linked thread), it's working with the general release version.
Unless MS had changed that with the general release version, this should work on a genuine Win PC. I want this option as I plan on running Win 7 while familiarizing myself with Win 10 at my own pace, if I decide to upgrade.