Warning upon boot (Take a look)

i also have a h815 ... locked bootloader
whenever the phone is rebooted i get an error message saying 'current version is not available for user. Can't find mathed cust for NT-code mcc/mnc[FFFFFF], subset[55]'
i'm planning on selling the device and i wish to do so without that problem
software version is V10c-OPT2-HQ
need help really fast
thanks

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