I have a Samsung Galaxy Note 20 5g (not ultra), I looked over at it just now and it has a bright green screen with the message:
"Security Error: This phone has been flashed with unauthorized software & is locked. Call your mobile operator for additional support. Please note that repair/return for this issue may have additional cost."
The top left corner has an error:
"Secure check fail : boot "
It was just sitting on a wireless charger and its like 4am cst. Reboots not helping. Even turning it off and putting it back on charger makes this screen pop back up. What can I do? No I didn't change anything. I just have regular google play store apps loaded.