Unlike a lot of other Android phones, the Dell Streak's microSD card slot is located next to instead of inside the battery compartment. This makes swapping cards (after unmounting) very fast and convenient . . . except that when the Streak's back cover is removed, the device turns off. Because of this behavior, the card slot may as well just be underneath the battery since having to take out battery to get to it would turn off the Streak too.
Wouldn't it be great if the Streak would stay on when the back cover was off?
It's something I've wished for often because when I transfer anything to the card, I always take it out of the Streak and put it into a tiny microSD reader that plugs into my computer. It's more convenient for me than using the cable, which I have set up inside a charging station, but I'm sure that being able to swap cards (again, after unmounting) is what makes the function particularly appealing to most people.
Whatever your reason for wanting this feature, there's a fairly easy mod that will give it to you. It requires some disassembly, though, so it may not be for everyone.
Note: DJ_Steve's latest Froyo build (version 1.4.6) already keeps the Streak on when the back cover is off because the system's "check for rear panel placement" has been disabled/removed. The following tutorial, then, is not for anyone using this version of Steve's amazing ROM.
IMPORTANT: Anything you do to your Streak is done at your own risk. Please proceed with caution.
All teardown photos are from iFixit.
1. Remove the back cover, battery, and microSD card for the Streak.
2. Using a plastic opening tool (like this one), remove the two pieces surrounding the screen.
3. Remove the five T5 Torx screws that are now exposed using a T5 Torx screwdriver.
4. Once the screws are removed, use a plastic opening tool to gently pry open the case.
5. Locate the small lever (circled in the photo below) near the ribbon cable. This lever is what one of hooks on the Streak's back cover depresses when it's in place, which means that anything that can "trick" the system into thinking the cover is on (i.e., the lever is pressed down) will allow the Streak to stay on when the cover is really off.
6. Here's where you can get creative. MoDaCo forum member tomqman, who was the first to do this mod (original thread here), used some hot glue to hold the lever down. Other members used a tiny piece of paper.
7. Reassemble your Streak.
If done correctly, you should now be able to take off the back cover whenever you want to without the system knowing about or being affected by it. Good luck!
Nice work, tomqman!