These articles detail how to change a ".bit" file into any required PROM file format.
NOTE: This Answer Record is part of the Xilinx Configuration Solution Center (Xilinx Answer 34904).
Solution
(Xilinx Answer 36210) PROMGen - How can file formats be changed or have files bitswapped? (Xilinx Answer 18884) PROMGen - How is the PROM MCS file checksum calculated? (Xilinx Answer 476) PROMGen - Description of PROM/EEPROM file formats: MCS, EXO, HEX, and others