As far as I know, if the value is 00 it means the light configuration is 'custom', as in: its not one of the preset configurations. Changing it to a preset still changes the light configuration only you cannot go back by changing bytes alone.The simple rule is that if byte 18 is 00 then modifying byte 18 is a seriously bad idea - because you don't know what the hidden code is, which means you can't go back to it.
Learned something new, thanks for the explaination!Hi Tommy,
The vast majority that are masked by 00's can be resolved by entering the proper value (providing that value is known) to restore all lighting. In this case I don't know what his would be. This car is very similar to a NAR NMS but that coding didn't work.
There however were some RoW market models where pre-ODIS required a GFF parameter test plan and current day ODIS does something similar because there wasn't an actual coding value (between HEX 01 and FF) that would fix them. If memory serves those were the late production 2009 (technically MY 2010) Skoda Octavias with PQ35 BCMs and that type would fall into your custom explanation if someone tinkered with it.