After the hard reset it will go back to Cyan ! i did it. so it should be update.
Were you in Developer Preview (in that case the "Denim" you saw was just a glitch in the Extras+Info)?
Performing a hard reset will not revert your phone to an earlier version of an OS - otherwise there will be no need to develop and release the Lumia Software Recovery Tool which is a considerable 58-104 MB in size.
However, there is a
rare chance that your phone will indeed receive an update after a hard reset... and that is IF a new OS/Firmware version is released to your region just right after your phone has finished recovering from the hard reset. Receiving such an update immediately after a hard reset may create the illusion that your phone has been reverted to an earlier version, according to the proposed timeline below:
Phone has Cyan >
Hard reset is performed >
Owner forgets what version was installed on his phone >
Update is released while the phone is being reset (coincidence) >
Phone finishes with hard reset procedure and
still has Cyan >
Owner sees "new" update >
Owner concludes that phone was reverted to a previous version.
If that was not the case and your phone indeed was reverted back to a previous OS/Firmware version after a hard reset, then it could be the first time for most of us (if not everyone) to have heard of that happening. We would then like to know how it was done since that would save a lot of users from the trouble of going through the Lumia Software Recovery Tool.
