Out of the box, if you buy a Raspberry Pi Compute Module 5, install it on the official CM5 IO Board, and install a fan on it (e.g. my current favorite, the EDAtec CM5 Active Cooler ), you'll notice the fan ramps up to 100% speed after you shut down the Pi.

That's not fun, since at least for a couple of my CM5s, they are more often powered down than running, creating a slight cacophany!

I created the forum thread Compute Module 5 Fan goes to 100% on shutdown , and through some back and forth, it was found the firmware on the CM5 needed a little tweaking to support powering off the fan completely on shutdown.

In this December EEPROM update , Raspberry Pi added some code to ensure the fan would power off (and stay powered off) on shutdown, but only if you have:

POWER_OFF_ON_HALT=0

In your Pi's EEPROM config.

First, make sure your firmware is up to date, e.g.:

$ sudo rpi-eeprom-update 
BOOTLOADER: up to date
   CURRENT: Wed  5 Nov 17:37:18 UTC 2025 (1762364238)
    LATEST: Wed  5 Nov 17:37:18 UTC 2025 (1762364238)
   RELEASE: latest (/usr/lib/firmware/raspberrypi/bootloader-2712/latest)
            Use raspi-config to change the release.

Run sudo rpi-eeprom-update -a to update to the latest version, if needed, then reboot.

To edit the EEPROM config, run sudo rpi-eeprom-config --edit , and add the following line at the bottom:

POWER_OFF_ON_HALT=0

Save that change, wait for the config to apply, then reboot.

Now, next time you shut down the CM5, it should be blissfully silent.

Hackaday user Eontronics also designed a modchip that can be soldered onto the CM5 IO board for a hardware fix for this problem, if you can't use the POWER_OFF_ON_HALT=0 option.