The only one on bitmain homepage:
Antminer-Z9-Mini-NAND-500M-201808311812.tar.gz

I tried both, keep settings and also unchecked it.
Did it several times and tried every combination.

the only tiny success:
installing batch 2 firmware --> change to turbo --> keep settings ---> install original firmware
Result: 550 frequency + working temperature sensor + working fan

sadly this trick does not work with batch 1 firmware and (e.g.) 650 frequency.
Keeping setting and reverting to batch 3 firmware resets the frequency to 500.