I would open a Sapphire Support ticket and see if they can send you a copy of the original vBIOS for your AMD GPU Card. If not for whatever reasons then you can go to TechPowerUp VGA BIOS Database to download one.
Here is TechPowerUp vBIOS for all Sapphire RX 570 4GB GPU cards: https://www.techpowerup.com/vgabios/?architecture=AMD&manufacturer=Sapphire&model=RX+570&version=&in...
I would download GPU-Z and click on the upper right corner "LOOKUP" to see the exact Make & Model of your Sapphire GPU card plus GPU-Z will show you your current vBIOS installed on your GPU card.
You then compare it to TechPowerUp VGA BIOS List to see identical ones to download. Compare GPU Speeds to make sure you have the correct vBIOS.