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.
please link with bacht 2 FW
Is from the official bitmain page so you know it has not been messed with. They kept it on their AWS site but removed the link lol.
Who has been "messing with" images?
Here are the md5sums of the image you linked to, and the one I host:
# md5sum antminer-z9-mini-201805262047-500m.tar.gz
0682b350dd8b53d62a11231d16d133a7 antminer-z9-mini-201805262047-500m.tar.gz
# md5sum Antminer-Z9-Mini-201805262047-500M.tar.gz
0682b350dd8b53d62a11231d16d133a7 Antminer-Z9-Mini-201805262047-500M.tar.gz
You will note they are the same.
Jason