Now you only need a slot one card to do this.
Follow the tutorial and use flashme_noauto.nds
http://gbatemp.net/index.php?showtopic=33481
Be very careful doing this, it is risky on a DS Lite. Make sure you protect the sides of your conductive tool. I used some electrical tape around a small flat head screwdriver. Remember if it stops updating just leave it on and repostion your tool over the contacts it will start up again where it left off.
Here is a quote from another forum on what it will do for you.
"What it does is rewrites the original firmware to flashme. It removes the health and safety screen, it disables the RSA secured feature..meaning you can use download play with homebrew and 'non' official nds games.
It adds the ability to use homebrew on your ds.
Some flashcards don't need this e.g Cyclods Evolution.
It also adds a 'recovery code' to the ds. So that, if your ds is 'bricked' and if the ds is still recoverable, you have the ability to force boot to Slot 1 or slot 2 to run flashme or no flashme to repair it."