Yahasun Auto Frunk installed the auto frunk in my car.
You can see in the photo below, they install a cable behind the small disk in the front bumper which you can easily pull out and push back in, which can be used to manually open the frunk in case of battery failure, or some other problem! (not the cables shown, those are wires used to connect a battery in case your small battery fails, and your doors won't open. They install another cable, not shown, which, when pulled, will release frunk latch)
Simply pop the disk out, find the cable and pull on it, frunk will release and open.
I happened to take a photo as he was working on my car.
As a side note... the wires shown in the photo, which are supposed to be behind this disk, were NOT there!
He needed to use a special, curved tool with a hook on the end, and fish the wires used to connect a temporary battery to your car in case of emergency, from somewhere in front of the drivers side wheel! He was nice enough to spend about 20-25 minutes fishing around and trying to find these wires, which he eventually found. I would have been up a creek if down the road, my battery failed and when I popped that removable disk out, expecting to find those wires, they weren't there!