I already tried FACTORY DATA RESET, Erase all data on SD card and phone/built-in storage and also HARD RESET.. but whenever i checked the system storage it shows that 1.20GB Os occupied.
then if i download some Apps .. even though i still have enough space for my SD card and in my built-in storage it always shows insufficient storage.. :(
please see the picture that i attached here..
please help me to fix my phone .. Thanks in advance :)