Samsung Galaxy S5 Verizon.
I have read all through this thread and I've yet to see a way to reset the ALTERNATIVE PASSWORD. First my fingerprint reader stopped working. It actually gave me an error message. Now the alternative password is not working (and no, I didn't forget it). I have used the ADM and I can reset my "screen" password from there but it does not help me with the Alternative Password. I can't delete the fingerprints using the Fingerprint Manager because it always stops me with the alternate password.
There have been a few updates to my phone from Verizon, but I can't get passed the Alternate Password to see if I can get the fingerprint reader working by replacing them.