Does anyone know where I can get previous firmware for M3 Real?

My M3 Real Card is messing up when i use the latest firmware but when i use the firmware i first got for the card (kept that for my sister's M3 Real) it works.
I want to test out to see if the 2nd to latest firmware will work properly and allow me to play my games.P.S. I have tried formatting the memory card twice and it still won't work with the latest firmware

Go to www.linfoxdomain.com/nintendo/ds You can find all the releases of firmware there. So you can try the second to latest, latest, or even 5 releases ago.As far as the latest not working? Maybe it's a different brand, and you got the wrong firmware.

^Unlikely, haven't heard of different variations yet.