The battery in my 2012 BMW 128i died. As a result, I removed the old battery to replace it. After battery removal, I closed the trunk. I should not have done that. The trunk latch of this BMW is electronically actuated via a button. This, I believe, is a weird BMW design flaw. Without a battery of any kind installed, I could not open the trunk to replace the battery. Nor could I jump the vehicle by using the positive and ground terminals under the hood, as the car's electrical circuit does not direct power to the vehicle through these terminals without a battery (even if dead) installed in the trunk. Pulling a mechanical cable under the passenger rear speaker, I was able to release the rear seat latch and crawl into the trunk. Finally, I opened the trunk by pulling the interior emergency trunk release latch. A new battery, then, fully resolved by dead battery issue. Relevant Amazon products are below.

2012 128i Car Battery:
https://amzn.to/4aGNKwg

Car Battery:
https://amzn.to/4aI3q22