Here is a very quick guide I found on how to use Action replay codes on your R4 card.
I only give instructions for the R4 but this works on the M3 simply as well, you just need to get the newest firmware, 1.04.
This is verified by myself, and it works great
Ok first, you need the latest R4 firmware, v 1.11:
http://www.r4ds.com/soft/english/English-1.11.rar Next you want the Code Manager from Datel:
US version:
http://us.codejunkies.com/nds_actionreplay/SetupUS1_05.exe Euro version:
http://us.codejunkies.com/nds_actionreplay/SetupEU1_05.exe Finally you want the R4 Cheat code editor:
http://www.r4ds.com/download-en.htm or if the site is down, then get it here:
http://rapidshare.com/files/32954884/Cheat_code_editor.rar Now it gets easy :-D
Update you MicroSD card with the new firmware
Install the Code Manager.
1. Under Subscriptions right click Codejunkies US Games and select copy if you want all or just do this for games you want.
2. Under My Codelists right click and select paste.
3. Let it import the games into your codelist.
4. Once it has completed go this folder:
C:\Program Files\Datel\Action Replay Code Manager\local_codelists
Find the XML, it should say something along the lines of customcodelist.xml
Open the Code Editor and go to file and press Import XML file.
Import the one you just made and then go to file and Save As cheat database. Save it as usrcheat.dat.
Now open the card again and navigate to the system folder. Copy the new usrcheat.dat file to that folder and you are done