If the bios chip is the same and it just came with the EVO bios, but the computer still boots and runs. The problem your running into is when your trying to flash it to a ASUS M5A97, the bios program sees the board as a EVO. Does the EZ flash have the option to over ride the error, if so try that. Pus you would need to update both the main and boot block.
Have you tried the Asus windows update utility. Dont do it from the internet, download and save the bios update and direct the utility to the saved update. On Asus I dont know if either program has a override to update even if the program thinks its the wrong update. If it bricks it again it doesnt really matter, if you cant save a change you would need to replace it anyway again. They should send you a new one for free anyway since they sent you the wrong one.