The Lumia Software Recovery Tool only offers the latest "Official" release for your device. Just as others have stated above. Let's look at this a moment. Using LSRT will have varying results. There is no "one answer" because each user is in some ways unique.
Using LSRT:
- Under 60% of active Windows Phones made the update from 8.0 + Black to 8.1 + Cyan. A user could be running Amber or Black and flash to Denim depending on their Region/Country/Model/etc.
- As mentioned above, any Preview for Developers advancements to the core OS will be lost when using LSRT. A user on P4D could be beyond 8.1.1 on the OS due to P4D and gain benefits of Denim level core App updates then loose it all and go back to 8.1 + Cyan by using LSRT depending on Region/Country/Model/etc.
- Your phone could be current with Official and using LSRT is a strictly lateral move and restores exactly what you had
It's always best to check the lists to determine what LSRT will give you. Remember to base this on your Phone's original Region/Country/Model/Carrier or Country variant. It has nothing to do with where you are standing or what carrier network you happen to be on - unless those personal conditions match the phone 100%. For example, I am in the United States and am on an AT&T mvno. LSRT will not give me an AT&T ROM for my 1520. It follows what the phone reports as; a Factory Unlocked, Latin America Region, Country Variant.
Here are the lists (Microsoft is pretty good about keeping them up to date):
Software update for Lumia with Windows Phone 8 - Microsoft - Global
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Using "Factory Reset" (Settings > about > reset your phone) or "Hard Reset" (physical button push combination):
- This will restore the last "system image" saved in the phone's recovery memory
And that's all it can do... Again, the results might vary by user. A phone that has never taken an OS update, will again be just as it was when leaving the factory. If your phone had updates then doing a factory or hard type of reset brings you to where you were at the last OTA that you installed.
It's important to note, if you have taken an OTA that has some bad code due to network interruption or other factors, all you can do by resetting to the system image stored in the phone is repeat the errors and bugs.
I don't believe that a Factory Reset or Hard Reset restores any P4D updates??? Anyone have more solid info on that?
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You can revert to earlier Official versions of the OS and Firmware or even flash a compatible ROM from the same variant, but with different Region, etc. That, however, is beyond the scope of the OP's question and a topic best left for elsewhere...
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