Download and install the Official Samsung USB Drivers on your PC.
Absolutely not. The GT-I9100 G has a Texas Instruments CPU. Flashing this will hard-brick your device. Seek files labelled i9100g specifically. Download Cwm Recovery V6.0.4.5 For Galaxy S2 Gt I9 Action
: If you are currently on stock Android 4.0.4 or 4.1.2, performing a factory reset or wiping data through CWM Recovery on a stock kernel Download and install the Official Samsung USB Drivers