I forgot to enable the OEM unlock while rooting a Galaxy Tab A 280 following the guide at XDA-developers. Now the phone is only displaying a FRP error on boot and shuts down again.
Download mode is working, but needs the correct ROM. I downloaded one ROM from sammobile, but installation resulted in the same error.
Where is the correct ROM to download? (Or is it possible to OEM unlock in this state?) If it helps, the serial number is R52H81KCSVW.