Software options for thermal throttling?

[Der Geist der Maschine]

That sounds super promising! Sadly, there seems to be some issue with the sensors:

Code:

$ sudo cat /sys/devices/virtual/thermal/thermal_zone0/temp
cat: read error: Invalid argument
$ sudo cat /sys/devices/virtual/thermal/thermal_zone1/temp
cat: read error: Invalid argument
$ sudo cat /sys/devices/virtual/thermal/thermal_zone2/temp
cat: read error: Invalid argument

Is this maybe why the device runs so hot? Is this normal...?

I don't have a PinePhone and can't help you further. You are on your own. What I would do:
 
1. learn your thermal settings

$ zgrep -i thermal /proc/config.gz


2. understand what these settings mean (and look for interesting settings not in your kernel)

https://elixir.bootlin.com/linux/latest/...al/Kconfig


3. understand the thermal driver's sysfs api (I don't understand why this file vanished from recent kernels) and see how to throttle

https://elixir.bootlin.com/linux/v5.2.21...fs-api.txt