Originally Posted by Sultan.Alkhuzaie
Can I downgrade from an NG2 base rom to an NE2 base rom ? I already updated the the bootloader and the modem.
You should be able to. In the past we've usually been able to downgrade a version. The notable exception is that Samsung blocks downgrading to Jelly Bean i.e. pre-4.3 vis a vis a qfuse flag.
I don't have a 900F, so I haven't tried the downgrade you describe myself. But the lack of reports about any problems argues that recent updates are "normal" and haven't set another qfuse that would block a downgrade.