Bottom line - jack up the front wheel on the side that's stuck, then pull on the hood and it might open.

Recently one of the two hood latches / locks on my 2008 R56 stuck and wouldn't open when I pulled the interior handle. This seems to be a rather common occurrence judging by the number of threads on this forum. I figured I'd share something I found in case it helps someone else.

After reading previous threads on the topic, I was all set to use a long screwdriver from under the car to push the latch open. I jacked both sides of the car up and put it on stands, and then pulled the release handle. I was then able to pull up on the hood and the stuck latch opened. After lubing everything up I closed the hood and tried it again, and it opened (no long screwdriver trick required). A few weeks later the latch stuck again when I tried to open the hood. I jacked up the front wheel on that side, and pulled the handle and then pulled up on the hood. It popped open. I tried it again a couple times to see if it would keep working, and it did. It looks like only the side with the stuck latch needs to be jacked for this to work.

I'm not entirely certain why this works. I'm guessing that lifting the front wheel off the ground changes the loading through the chassis and makes it flex in a way that either adds force across the latch or reduces it. This would jive with similar threads that say to have someone either pull up on push down on the hood as you pull the handle. This trick is something that can be tried if you don't have someone to help (as I didn't), so maybe it's got a use to someone.