After flashing StockMod G2 automatically booted into CWM and when I wanted to flash back to SlimKat it said: "Unable to mount /SDCard!"
I tried to install TWRP recovery and tried to fix it trough the recovery, but it always said unable to mount sdcard. Finaly I got rid of that error by formatting all the partitions. After that I installed several via ADB Sideload, but every ROM "installs" and when I want to boot it goes into recovery again. So, I noticed that my /system partition is never mounted and I can't mount it.