Does Downgrading from Android Marshmallow to Lollipop wipes data?
The problem is not just whether it will wipe your data.


Many phones have a mechanism that prevents a downgrade in bootloader version, which you're attempting to trigger.
Older version of an app might not recognize the data created by the newer version of the same app. Although user apps are rarely affected, crucial system apps might be, and on error might constantly throw "*** has stopped" dialogs that effectively prevents you from using the phone.


So no, just don't think about downgrading as a means of restoring data. Instead, focus on dealing or working around the PIN, which you could check out the locked-out tag for a head start.