Thanks for your reply. I will try with tftp and see if I have any luck. It's really wrong and selfish to lock down products you paid for, and on top of that, it's more frustrating that they lock...

@David-TP Thank you so much for your respond, basically there is no way to patch back to original firmware over ONZ ones.

Hi there , I have deco x50 from One NZ (ex Vodafone company) problem is deco comes with ONZ costume firmware , 2.0 something, I manage to flash 1.2.2 original firmware and finally I have working VPN...