The mistake is your phone is CERT: BROWN with EROM CID49 and you try CERT: RED files (CID52).
With Omnius change to RED 52 and then can flash with:
1. K850_R1FA035_MAIN_GENERIC_SO_RED52
2. K850_R1FA035_FS_WESTERN-EUROPE_RED52
3. K850i_1201-0077_R11A_GENERIC_WESTERN-EUROPE