HELP - k850 keypad not working perfectly after instal new firmware!!!

hello there, i had problem with my SE K850i phone.
my keypad num 2,5,8,9,* and # also call button not working after i instal new firmware..
the keypad sometime work when i use..but now it cant use anymore.
it's because of the firmware or hardware problem? i had tried install onther firmware but
the keypad still not working perfectly!!
i use ;
K850_R1FA035_MAIN_GENERIC_SO_RED52 - MAIN FILE
K850_R1FA035_FS_APAC-ANZ_RED52 - FS FILE
K850i_1201-0102_R11A_GENERIC_APAC-ANZ - CUSTOM FILE

change keypad membrane and post result