I owned the BMW E46, whereas my friend had the BMW E90.
He inquired about the functioning of the device, to which I responded by instructing him to press and hold the button for a little duration, similar to how I operate mine. Furthermore, I demonstrated the operation of my device to him.
Attempted the same procedure on his vehicle, but, it proved ineffective, leading us to conclude that there was a defect specific to his automobile.
After a span of 2 years, I purchased his automobile and one day, while casually experimenting with it, I inadvertently hit the boot button, causing it to open unexpectedly.
Subsequently, I saw that the automobile was not secured, prompting me to attempt the action once again. This is how I discovered that it only functions on the e90 model when it is in an unlocked state.