There is no faster way to fix this problem if you don't provide necessary info.
Not sure you have follow my mail below to restore the original option feature back. Please advise?
If originally this unit has the NIV feature, and you can't turn it on from the service menu/options key, then pls provide the followings (if possible with photos):
1) Unit serial number
2) Unit key/BID label in the back of the machine
3) attached the option key under the service mode shown in the display
4) also attached the options list under the service mode in the display of this unit
I will need to approach factory engineering for their assistance to obtain the correct option key.
Once we got it, your engineer will still need to go to the service menu/options key, and then enter this key code that will take the machine back to the original options (if unit has the NIV).