I'm using 4-pin PWM fans for case and CPU and like that they are setup in BIOS.
The fact is that the latest BIOS version which had perfect fan control without any issues was 4804. From then and on every new BIOS had the issues of random 0 RPMs or full RPMs.
I've found out that the Asus WMI version was changed after 4804. There is a note in github of FanControl app (for the ASUS WMI plugin), saying that it supports X470-F with 50xx BIOS version and newer (Asus WMI GEN2).
On the other hand, only full RPM for the CPU fan is occuring with latest BIOS, every 3-4 hours.
Quick update after some emails to Asus support, regarding my fans issues.
They are unable to give me a solution of going back to 4804 due to the reason that the motherboard does not have a flashback feature.
They never replied to my solution of giving me a BIOS that will allow to flash an earlier BIOS but they telling me to send over the motherboard for service! And that without any information from my side of connected fans, fan type, which fan connectors etc. And general they did not ask me for any information regarding my issue, so for them to replicate it and -why not- fix in next BIOS version.
How this is going to help me better and faster from a unlocked BIOS version to allow me to return to 4804 which has no fan issues at all ?
Typical scripted support answers without any meaning. They also purposed to reinstall Windows to see if the fan issue will resolve itself!!! It is 100% clear that the BIOSes after 4804 have fan control issues under circumstances and to be exact the Asus WMI is crashing randomly, leaving the fans in their fate of spinning full or not at all!
That was for me then. I'll never use a Asus motherboard again as it seems their after sales support is scripted to waste the time of users, making them to skip support and buy new hardware.
I know some of you do not have issues -for now, but when the time comes to ask for support, you will come to the place I am right now.
There is a possibility for the given guide to not work due to the BIOS format of the motherboard. There are '4804.cap' and not '4804.rom'.
Reading more deeper for that, converting .cap BIOS to .rom hides greater risks and possible will brick the motherboard with error -43.
Thanks for the hints though caas.
At worse you can flash the bios chip using a programmer (avoid CH341a) and an SPI cable adapter (search for 1005003066966123 in AliExpress)
Asus CAP file can be easily converted to ROM file using UEFITool.
The only concern is to recover beforehand the UUID MAC & MB Serial before flashing the bios, which can be done easily using FD44Editor.
Values can be easily extracted using this shell script (save as CMD file).
Also, this might help you understand the idea better: