AB350 Gaming ITX CHA_FAN1 not working

Hello,

I have an ASRock AB350 Gaming ITX motherboard with a Ryzen 5 2600.
It was running fine under UEFI version 6.20 but that was quite old and vulnerable to a number of attacks so I decided to update it.
I first updated it to the bridge BIOS version 7.00, and then to the latest version 10.50 (dated April 8th 2026).

The update went well but since then the CHA_FAN1 header on my motherboard stopped working. The fan connected to it works properly if I connect it to the two other fan headers of the motherboard.
I really need all 3 fan headers on my motherboard to work because I want individual parameters for the CPU radiator fans, the water pump PWM and the rear exhaust case fan (connected to CHA_FAN1).
My rear exhaust case fan is a BeQuiet Silent Wings 3 PWM 120mm. I made sure it responds well to PWM on the CPU_FAN header (accelerating, decelerating, steady speed etc).


I have read some people experienced similar problems with other ASRock motherboards after BIOS updates and solved their issue by disabling USB Power On, but this did not solve the issue on my motherboard.

I also tried loading system defaults --> no improvement
I also tried clearing CMOS --> no improvement
I then tried to roll back to BIOS version 10.43 Beta --> no improvement.

I cannot roll back to version 6.20 since it is too old for a roll back (if I understand correctly).

I also want to mention that this malfunction is independent of the OS. I see this behevior even before OS startup and when navigating the BIOS : the rear exhaust fan is stopped. I have taken a couple of screenshots in the BIOS. CHA_FAN1 speed is reported as "N/A".

Could someone please help me solve this issue? Thank you in advance.

Hello and thank you for your reply.

I have tried to clear CMOS as you suggested but this did not change a thing : the CHA_FAN1 header is still unresponsive.

I have noticed that CHA_FAN1 is not even reported in HWInfo64, which makes me think this is a software/UEFI error.

Here are the screenshots :

When I was running v10.50 :
https://imgur.com/v1YjNuO

You can see "N/A" in front of CHA_FAN1 :
https://imgur.com/5kHrue1

And here is the screenshot of HWInfo64 with CHA_FAN1 missing :
https://imgur.com/hh6iQtj

(Sorry for the 3 replies in a row, this forum lacks the "edit message" function)