I'm using the stock firmware and the fan works "reasonably well".
I've spent a lot of time trying different settings and observing the effect...
$ sudo shutdown --poweroff now
and it works. The fan stops. Thanks for that! :-)
Interesting... I'm using Unix systems since 1985...
I'm using Debian 10.2 on an UDOO Bolt V8.
$ uname -a
Linux mercury 5.3.0-0.bpo.2-amd64 #1 SMP Debian 5.3.9-2~bpo10+1 (2019-11-13) x86_64...
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