If you have already flashed the 4.1.2 you can just select the files you want to flash (remember to always flash the preloader and DSP_BL files).
If you flash the EBR1 file you need to wipe and restore factory defaults..
wait what?? i just flashd the ebr1 file after i was nearly finishd with everything then i saw the 500mb internal memory only... and i did not reflashd the preloader or dsp_bl file...