Use A2uploader from here: a2uploader and CID53? - Top Sony Forums and these files:

C510_R1FA035_MAIN_GENERIC_KT_RED53
C510_R1FA035_FS_WESTERN-EUROPE_RED53
K850i_1201-0077_R11A_GENERIC_WESTERN-EUROPE (no problem with K850, because C510 use same custpack)