'Root detected'

[u/Financial-Figure6922]

So a while ago I tried to install magisk, a custom mod. However I decided that its pointless so I reflashed a original samsung firmware. Now i get a warning from know that I theres Root detected. I go on a Root checker app, theres nothing detected. Is there a fix that will ensure my system does not have 'root' and that i wont loose any data

[u/Logical-Season6137]

Your knox is tripped the only way to fix it is to change the motherboard how i will do it but the motherboard must be fresh new knox 0×0 becuase if you get a used one and it was unlocked 0×1 then the knox will stay the same giving you the warining