I have the m3ds real and I'm using the latest firmware for it G6&M3DS-R_E35 v4.2 and recently I ran a .nds file on there that froze my DS, when I turned it off then back on it started the following, It will load everything for a second at the main menu screen then the bottom screen will go blank(black) and the DS wont do any thing If any one can help I would very much appreciate it. thx. So far I've formatted my card, Placed a fresh copy of the system file on there, and placed all of my .nds files in the newly created "nds" folder. Oh and I'm 100% sure my m3ds real card is legit I've never had this problem before and I've had the card for about 6 months.
If it was working - then it has to be legit - fake cards don't run M3 real software. Try formatting your card with the following panasonics sd formatter (use google to find - its free) This solves a lot of freezing issues as windows does not format sd cards properly - if your using MAC then ignore this.
I actually have that already but thanks though. Thats how I formatted my card originally, Oh and I wouldn't be caught dead with a mac so... (no offense to you mac users though ) also I've found a temporary solution I'm having to use a regular DS instead of a DS lite but it's the only working solution that I could find anywhere.
Try using NDSTokyoTrim, use this to check all your files, there have been none for a long time but there used to be files that would brick your DS. This program has a basic check for bricking files