This is somewhat one of those questions we regularly receive from the customers who purchased genuine parts (mostly genuine sensor, Camera / color screen)
The general & ordinary answer to that question will be 'You code it'.
At some point It's true, but not every ECU will consider coding as a complete solution.
For example, even If you've coded the ECU to allow it to install a genuine electronic accessories and now ECU is open for it, some accessories will require different pin, dedicated wires or harness to be installed - which often the car didn't come with.
Let's make an example based on Volkswagen.
Volkswagen Golf Mk6 had an optional package that included a 'Badge' flip Rearview Backup camera, genuine as It could be and lots of people wanted it.
Meanwhile, there were 2 types of optional audio systems available for most of VW vehicles.
known as RCD 510 and RNS510, shared between vehicles apart from Touareg and Phaeton, which never landed to Australia.
RCD 510 and RNS 510 both had same 6.8" Touch audio screen, yet RNS version had built-in GPS Navigation and better resolution (800 x 480p)
Due to those options were way above what you can think of (RCD 510: >$1600), (RNS 510 : >$2500), some people thought that 'Hey, why not I just grab a RCD 510, fitted on my Golf and purchase those genuine badge flip camera from online and install it with coding?'
It does work and the coding will allow the camera to be installed into it, and theoritically It will cost less than purchasing it from dealership.
But the problem was that, VW Badge cameras were designed to be fitted on RNS 510 only, not RCD 510 - due to Badge clip was coming with RNS package, not RCD.
It's designed to come with Blue LVDS & GPS port, that most of genuine badge camera has (male port), whilst RCD 510 doesn't have female one, as It doesn't have built-in GPS system.
And then, there's another concern, which is that RNS 510 is hard to be installed to those vehicle that wasn't assembled with it from factory, which requires intensive coding, and even the 2nd hand with good condition one costs at least $900 AUD.
Again, this is just an example of what It's like to install a genuine accessories to the car, as mentioned, sometimes genuine system won't be fitted to the car even with coding because It's blocked from assembley, or the ports aren't available.
Hence you will get why dealership often declines your request, when you actually purchased the car first then try to upgrade to genuine premium package.
But It doesn't mean the car will never have the accessories to be fitted, either genuine one with lots of time, money involved with updating ECU, software and coding.
Or choose an aftermarket one.
Let's say you've purchased a BMW E60 5 series, which was once a hot vehicle among people now becoming a royal saloon for teenagers and early 20s.
Consider E60 was first introduced back in 2004, those vehicles didn't really have what the current cars in 2016 have.
Having said that, in that matter the BMW E60 vehicles did not have neither Rear Camera nor Bluetooth audio streaming feature till the iDrive upgrade - done back in 2008, conversion of CCC to CIC.
Obviously the car is outdated and dealership won't be supportive with your issue.
And for the aftermarket - unlike E90 3 series, E60 doesn't really have much solution - due to It's simple designed audio dash - there's not enough room for double din unit to be fitted.
And then there's an iDrive display, located over AC vent.
Interior of BMW E90 - for reference.
Although It should have limited features to compare to moderen ones, yet you do notn want to lose it due to It's a genuine system and you'd like to retain it for resale purpose.
The good things is that, there's a way of installing an accessories, such as newer GPS / Cameras, bluetooth etc, without chaning nor removing anything from the vehicle, not just BMW but most of brands.
It's by using decoding module, to not just open a way for accessories to be fitted, but also an aftermarket system to be fitted and perform like genuine ones.
This is the video of the Rear camera installation opn BMW E60 525i model, with using decoding module.
Basically what It does is that: the decoding interface will open up input for accessories to be installed, and also, It will grant those to be connected to the car, using its bypass system to gt it powered by the car, whilst display or play it via Car's audio / electrical system.
Hence It allows you to connect aftermarket accessories to be installed to the car without coding nor struggle to finding the right port from the car - as the car will never have port made for aftermarket accessories, and the decoding module will do every coding for you.
Which, us Naviplus are specialized in.
The perk of this decoding module system is that, It doesn't affect car's appearance nor performance.
As It decodes and re-codes the system to adop the new system and allow it to perform it like genuine parts - beside, the quality of aftermarket has been significantly improved.
So pretty much instad of using those cheap eBay accessories - those connected on cigarette light / fuse box or replacing audio system to something else, this decoding module will surely come handy and legit solution.
Extension to that, this has been helped out lots of our previous customer, who purchased a camera / GPS Box from the online as It says their car is compatible, yet gave up on installing it due to there's no such connectable port available.
There's been at least 8~10+ customers for each Audi, BMW, Merc and VW who came with genuione accessories to Naviplus and hired our service and decoding system.
Although our systems aren't completely designed to provide connection for genuine accessories, It will provide OEM and OEM style aftermarket accessories, with OEM quality performance guaranteed.
Tested and proven in Australia via many vehicles from those brands with famous for 'code to install'.
Us Naviplus has most of European vehicle's solution in stock, and happy to assist you if you have a genuine / aftermarket accessory itself, and wish to get it fitted through our flawless decoding interface system!