Even after installing stock rom the traces of custom rom don't go?

[AC Question]

Few days ago i added custom rom in S6 and it was called alexis rom. It was note 7 rom on s6. I clicked to install note 7 bootloader. So note 7 always comes when i power on. I even installed stock rom from odin but note 7 bootscreen is not going . What should i do to remove it?