Pelican Parts Forums - Jumpstart tab

The other option is the emergency pull cord under the right side of the bumper accessible via the wheel well.

Some of what you can do is model year dependent. I'll list all the methods I've ever heard of, you pick the one that applies to your model year and for which you have the equipment.
CAUTION CAUTION CAUTION - OBSERVE POLARITY WHEN DOING ANY OF THE ELECTRICAL METHODS BELOW.(Polarity means don't connect positive to negative or vice versa.)
First method
And probably the simplest is to go to Radio Shack and find the adapters for the Cigarette Lighter Plug with Banana Jack adapter (Cat # 270-1521).
This sells for about $8. It plugs into the accessory jack and the other end has two terminals, one red and one black. Get yourself some color coded cable as well and then connect to a good battery being very careful to observe the proper polarity. You'll probably have to hold the adapter in the accessory jack as the Porsche lighter socket is slightly larger than for American/Japanese cars in some model years. You should be able to then open the front hood. You can also get two of the adapters, run wire between them observing polarity, and then connect between two cars. CAUTION: don’t attempt to start the “dead” vehicle in this manner. Because of high starting currents damage is highly likely to occur. Use this only to get the front hood open, and then jump the car in the normal manner should you chose to do so.
A slight variation on the above: If you have a friend that has a charger with cigarette lighter adapter try plugging it in and waiting an hour or so. If you can get another car near it you can also go to Radio Shack and get two cigarette lighter adapters and string up some wire between the adapters (make sure you have the same polarity at each end, connecting center to center and edge to edge. That usually means the colored wires change where you splice them.) and then plug it in to another car. Again wait a bit and then try the trunk opening, don't try to start the car that way as you'll draw too much current and fry the jumpers you just made.

Method two.
Some people have also reported that a battery maintainer which plugs into the accessory jack will also allow you to pop the hood. I think I remember that you need to have it plugged in for an hour or so to get some level of charge on the battery before the hood release will work.
Third Method
Inside the top of the driver's front wheel well, just aft of the spring coil mount, is a little rectangular corner in the black plastic shroud that lines the inside of the wheel well. Reach under this, and you will feel a "wire" about 1/8" in diameter. Too thick for an electrical wire (and not in a harness anyway). Tug this cable gently out from behind the shroud and get a good grip on a loop of it. Now pull hard away from the headlight once, and prepare to hear the music of the alarm as the front hood pops open. Grab a 10mm wrench and take off one of the battery cables to silence the alarm.
Eric adds:
"If you lay down under the front bumper you will see 4 openings and you can look all the way up them to the hood. The space between the trunk and bumper.
All the way up on the passenger side you will see the piping for the AC. (at least that's what I think it is). In my case I was also able to see the 1/4" cable that runs from the trunk latch towards the passenger front wheel well.
I was able to reach up and hook that cable and pull down on it to open the trunk, I then rerouted the cable making it easier to do again if needed.
I actually used part of a plant hangar my neighbor had in his garage and a flashlight so I could see what I was doing. It would help if you could jack up that side and stabilize it to make it a bit easier to get under there."

Fourth Method
...and from the Porsche TSB.
"Should the front and rear hood releases become inoperative due to a disconnected or discharged battery, the following procedure will allow the hoods to be operated electrically under these conditions.
· Open the left door.
· Using an external battery, connect the negative lead to the door stop.
· Connect the positive lead to both sides of fuse "C3" (see illustration below).
· With the door open, move the door latch with a screwdriver into the closed position.
· Using the key, lock and unlock the door.
· The front and rear hood releases can now be operated.
By the way there are several batteries that people have used successfully. I replaced mine with a Sears International Diehard at about $100. (Mike interjects here to suggest going to my page on batteries for a complete list of batteries known to fit the Boxster.) I don't remember exactly which one but it was correctly shown in the Sears computer database. When replacing, empty your front trunk and actually get into the thing with your feet on the floor. Then changing the battery becomes easy. Otherwise, it is very cumbersome lifting from the side or front when you are outside the car.
When and owner called Porsche because he was still having problems, they suggested:
1) You need to try to open the lid using the KEY REMOTE, not the switch on the floor
2) Since the front lid had been sealed shut for 4 months, he said to press down on it (on the Porsche logo) and try to prop it up while trying to open it. Sometimes the rubber seals stick enough that the lid doesn't have enough oomph to pop open.
Fifth method
Applicable to MY1997 thru MY2000 (compliments of Joe King):
To open the front trunk when the battery is dead you can use the emergency release cable which can be accessed with a few tools, use the battery procedure outlined in Porsche Technical Bulletin 1/96 5510 or use my method which requires a small screwdriver and flashlight. It allows you to open the front hood lid in about 10 seconds once you learn the trick. My procedure is outlined below:
1. Both trunk levers are cable operated. When the alarm is set, a solenoid latches the two trunk levers. If the battery dies while the alarm is set, it is necessary to open the door with the key. Opening the door with the key does not unlatch the trunk levers since there is no power to operate the solenoid.
2. To learn how to unlatch the trunk levers, examine under the front trunk lever by looking through the slot between the two trunk levers with a flashlight. Look for the tab on the underside of the front trunk lever. Directly below the tab is a small U shaped cutout. When the lever is pulled up, the tab drops into the small U shaped cutout. When the alarm is set, a small white plate slides over the small U shaped cutout from the center of the car towards the outside of the car. This prevents you from pulling up the lever because the tab cannot pivot down into the small U shaped cutout.
3. To unlatch the front trunk lever, use a very thin shaft straight slot screwdriver (I used an Xcelite R3323 which has a very thin 3"shaft). Slide the screwdriver between the two trunk levers and insert it between the solenoid plate and outside rear edge of the U shaped cutout and slid the plate toward the center of the car and pull up on the front trunk lever.
To test this procedure (without waiting for a dead battery):
1. With the drivers door open, move the black door latch to the closed position, the second click. This is done by using a screwdriver to move the black lever portion of the door latch toward the outside of the door until you hear a distinct click followed by a second distinct click. IMPORTANT: At this point do not slam the door shut since the door latch is in the latched position and may be damaged when making contact with the door jab. Step 4 explains how to reset the door latch.
2. Lock the car using the remote or key. The alarm will be set and the trunk levers latched. Don't sit in the car because the alarm is set.
3. At this point you can use the above procedure to open the front trunk. The alarm may sound when you pull up on the lever since you are opening the trunk. This is determined by the front trunk switch adjustment.
4. IMPORTANT: After opening the front trunk using this test procedure you must unlock the car using the remote or key followed by pulling up on the door handle to unlatch the door latch.
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My '01 has a red covered tab inside the fuse box that has a picture of the front hood opening. That is the positive connection point for an '01 Boxster.