For me, the problem was the fact that I had made a hotspot without connection to the internet. When the 3DS can't reach conntest.nintendowifi.net, it will disconnect, and crash the CFW.
Also, when you start the CFW with the "L" button, don't touch anything, wait until it's connected to your internet, and then spam the run.bat.
I've been able to set it up multiple times on different SD cards (2GB, 8GB, 16GB).
Also, when you start the CFW with the "L" button, don't touch anything, wait until it's connected to your internet, and then spam the run.bat.
I've been able to set it up multiple times on different SD cards (2GB, 8GB, 16GB).