lolipop updates for htc m7

dear all,

I m a user of htc m7, I tried bootloader to update the lollipop but not succeed. my phone is rooted but I don't know the problem why it is not updating as well auto and manually.
in the setting when I check for updates nothing happen.
while doing manually through PC in the end sending updated(0/5.......................) showing and failed after half and hour.
please help me to update lolipop update.
thanks u
please inbox me the solution
sinister5029@gmail.comm