Firmware question

[BitStarMining]

I'm wondering which firmware to use for s9 14Th. The statement on bitmain says "Support S9 miners except S9-11.85T，12.93T，14T with fixed frequency." The miner in question is Dec batch. One hashing board not working. Just figured I'd try to flash to see if that works before sending back.

I'm not clear if frequency is fixed or not.