I have managed to update to 2.5.1 on my NP2, this with an EE A device brought to Mexico, since the official update has not yet dropped, I have been able to update from 2.0.4 stable to (open beta 2) 2.5 and from there to NOS 2.5.1 stable,
all this with the help of @AmirHussaini.
The bad thing is that you have to factory reset the device to avoid any errors.
now I will enjoy NOS 2.5.1