Checking Android devices for Originality

Hi. Is there a way like online originality testing system or application to check if Android phone|tablet|other_device has been 'tampered' with aka installed different firmware in secret with Odin or other app and|or action. I have suspicion that some device(s) could be "infected" but to make sure i need to check if firmware is original etc. and that none other flashing etc. is done in secret to spy or w/e.