i guess you gonna need to start here for CID53 : Flash K800 CID53 with K810 software CID53 (for begginers) - Top Sony Forums
but use files only specified below :
MAIN : K800_R8BF003_MAIN_GENERIC_WI_RED53
FS : K800_R8BF003_FS_EUROPE_2_RED53
custpack : HB1-06_Gen_CDA102568_11_R8A_GENERIC_EUROPE_2