For C902, choose any firmware you want here : Top Sony Forums
But before flashing your phone, you go to setting-->general-->update service-->software info . Then see your firmware is Rxxx0xx_RED53. Then you download the firmware that is same.

For W995, choose any firmware you want here : Top Sony Forums
But before flashing your phone, you go to setting-->general-->update service-->software info . Then see your firmware is Rxxx0xx_RED53. Then you download the firmware that is same.

Then , click search option, and change the files type to Compressed, and also click large for the file, because most of the firmware files is large. After searching , something will name like this is a firmware "W995_R1EA033_MAIN_GENERIC_HI_RED53" and "W995_R1EA033_FS_RUSSIA_RED53"