try mo magdelete ng unwanted files mo lods, cache ng apps. try mo rin go to file manager > MIUI > then delete mo yung "Gallery", pag tinignan mo details nun aabot yun ng mga 2gb, no worries naman kasi cache lang yun ng deleted photos. other than that, reset mo nalang phone mo lods. sakin umabot din ng 12gb yung system kaya napilitan na ko magreset. sana nakatulong