Acabo de instalarlo y me sale al entrar en
recovery lo mismo.
System Partition
Unmodified system partition detected
TWRP can leave your system partition unmodified to make it easier for you to take official updates.
TWRP will be unable to prevent the stock ROM from replaciong TWRP and will not offer to
root your device.
Zip installations or
ADB operations may still modify the system partition.
Debajo me aparece un recuadro para activar que pone "Never show this screen during boot again"
Y debajo para deslizar que pone "Swipe to Allow Modification".