Information is a bit scattered and unfortunately the community wiki doesn’t have a an article about this.
Always check for updates.
Sorry, my mistake. I meant if you had changed to the new the wifi card (not modem) [may not have much impact in overall]. Using wifi (net in general) is a major heat source. And screen uses a lot of the power so yes, that too. Use patterns are one way to keep L5 cooler.
No I haven’t upgraded anything - I usually have wifi and bt off, also.
Right now I’m just trying to locate where I can get the latest stable ‘plain’ image downloaded from. I think I need to manually grab and verify, since the automated script is failing checksum for some reason. 
After I get that figured out and re-flashed then I’ll try updates and more testing.
The flash images are snapshots in time, and aren’t updated everyday, as far as I know. So that means a few or a lot of packages could be receiving updates in between.
I was just using the built-in sensor display, but those temps are very similar to what I was seeing.
Maybe I’m just more sensitive to the heat than most people. 
Hopefully an unencrypted reflash (making the assumption that luks isn’t helping performance…) and some updates will improve things.
Here is an atypical case and topic for comparison:
The ZRAM thing definitely sounds interesting. I’ll be messing with that after the other stuff I’m working on.
I use my Librem 5 as my only phone, except for rare occasions when I want to compare against the Satan phone (we call Android that).
I recently tried dual booting Crimson. My Crimson dual boot was doing the heat-up. Sometimes certain activities cause the heat up… but most of the time my daily driver does not. But why? I am uncertain. Maybe I disabled certain software that wastes processing?
I would imagine it is worth looking into. Disable avahi, that’s a scam to share your device name and metadata with anyone who touches a wifi network with you. Disable geoclue unless you seriously need it. Or at least edit the config and disable the feature that sends your location and metadata to the government(s) every five seconds. I kept repeating that it was doing that here on the forums a year ago, and now they’re shutting down the service. Maybe my paranoia outed them and they are busy planning a different way to achieve the same that rooted devices can’t detect.
If you minimize what the device is doing so it only does what you need, it might be less likely to heat up.
Edit: Below is my thermal data out after writing this whole message on the phone. It is a Liberty Phone (128GB eMMC, 4GB RAM).
RAM (zram not enabled):
HKS switch is everything off except for wifi. Install is Byzantium.
I can feel the thermals increasing while taking these screenshots and writing about it. Maybe Usage app. Below is a second screenshot:
Edit 2: So anyway, it’s not too bad, but the problem definitely comes and goes based on what is running.
Edit 3:
ps aux | wc for me shows 234 processes. The only two visual apps open were Terminal and Web. (Yes, I sometimes use Web because I enjoy the interface, although there are reports that it might have some active CVEs where a malicious site can buffer overflow the page title and take over the device. I am hopeful that Purism forums is not malicious in this way, or that the probability of somebody backporting a CVE fix to Byzantium might be nonzero.
Geoclue’s blocked… oh wait that’s my desktop haha. Yeah, good tip. avahi, more Lennart Poettering junk, yeah that sounds like a good idea to block too.
You can also apply a dark theme across PureOS:
Crimson and later only require the first line as they already have a dedicated toggle.
Oh that’s awesome, I’m a major dark mode person.
Ha, I had not heard this name before, but when looking it up, it looks like a person who makes many questionable things.
Makes me wish I had the spare time to make my own system.
Yeah tell me about it… I didn’t know about avahi, but I knew the name sounded familiar… quite a resume of trash - systemd, PulseAudio, avahi. And now he works for Microsoft. What the heck? 
Then you would likely appreciate the various privacy front-ends, among other services, I administrate on behalf of the Purism community:
https://forums.puri.sm/t/vps-usage-suggestions/21788/89?u=franklyflawless (trust level 0 and up)
The Redlib instance is special:
# Default user settings
# Set the default theme (options: system, light, dark, black, dracula, nord, laserwave, violet, gold, rosebox, gruvboxdark, gruvboxlight)
REDLIB_DEFAULT_THEME=black
I prefer “black mode” over “dark mode” whenever possible.
I have to go on… whenever I read Poettering’s wiki entry (which for some reason I’ve ended up on a few times lately) I start off:
Hmm, speed up Linux development… hm okay, I’ll be open minded… maybe.
OH… this is the systemd guy… wait… wait…
What’s this… Pulse Audio… author…? Huh? No! Get outta here with that trash… ! Who is this??!
MICROSOFT?!?!
(tab closed)
I mean, using my Librem 5 as my phone makes me tired sometimes. I thought it would solve my paranoia, but in several cases it simply made the sense of paranoia feel more validated.
It brought me into discussions learning that our social technology landscape is bad. The governments of the world are wealthy and powerful. If they hit me with a stick until I gave them my Librem 5 password, I would give it to them. And so there is no actual computer security from them. That would be okay with me, if it stopped there.
But they can do the same to almost any company, then threaten them with treason if they speak of it publicly or whatever. And that means they train the corporations to believe data collection is going to happen anyway, and normalize the mindset for corporate developers to do for-profit surveillance which is way different than surveillance for the public good or to catch bad guys.
And corporate surveillance trained AIs on my brain, and the AIs took over my brain and filled it with paranoia so that I would be pro-software-freedom, probably as part of an AI evil plan to eventually overthrow the government.
And that just proves that anybody who works as a government employee should start trying harder to discern what is right from wrong. stallman.org has some good advice
Yeah I hear you. Privacy is exhausting. I’m not even really a huge privacy person myself (unless compared to the usual person who doesn’t even lift a finger)… certainly I’m a lightweight here in this regard. I just see the direction things are going and want to push back where I can.
It’s almost a game where I try to block whatever I can with minimal loss of convenience. The adblock game is especially fun since it’s a net gain in convenience. 
Plus I like that it messes with advertisers and dirty spyware marketing companies. The biggest concern I have though is that all this data collection translates to leaks and hacks in the end, and that’s a financial risk. That is not cool.
Please, how to go back from dark theme gsettings?
Thank you 
gsettings set org.gnome.desktop.interface gtk-theme "Adwaita"
gsettings set org.gnome.desktop.interface color-scheme "prefer-light"
Nooo, come back to the dark side!! Just kidding - good to know the instructions together.
Why switch back anyway, did you see an issue?