I dont know if it bothers you but if you unscrew the modem cover, the A1 or E1 label (or the other third variant, I assume) is visible.
I have a Librem 5 and two Liberty Phones that I alternate between. I was daily driving them from March 2023 until June 2026. (After that time for work I went and bought a sad android spyware machine, and then was pressured by my work to take all of the sim cards I had and put them in the spyware machine. I continue to nearly always carry my real phone (liberty phone) with me though as well as the work phone, since I assume the spyware device is just there to tie me over until AI rewrites all software so that then (proprietary) software is no longer the Achille’s heel of the Librem 5 so it fits fine into modern society.)
Because of the above, I own three A1 modems and an E1 modem. Typically if I travel overseas, I switch in the E1 modem by physically unscrewing the cover and the A1 and removing and replacing the A1 with an E1 in my primary phone. As a note, one of the first times I swapped modems in this manner without reading the Purism guide pages/wikis, I physically broke the modem. You can probably find the story here on the forums. So somewhere I have a fourth A1 that is damaged probably buried in my storage of old things. I was able to show it can physically work fine if certain parts are held in place with electrical tape, it’s just a matter of knocking loose a physical part of the device.
I am skeptical that the E1 in the wrong country causes increased heating. Even with A1s, Librem 5’s run hotter and run out of battery very notably faster if the modem HKS is allowing power to the modem. If it were up to me, I would encourage people in my life to use open protocol, libre software encrypted internet data communications instead of SMS and calls. (Then I would only power my modem while outside WiFi, and otherwise cut power to it, which was often my habit these last few years.) Historically some nation state actor or something made most of the encrypted chat apps disappear mysteriously unless their encryption was bad or if they were tied to nonfree nonrootable devices with client side scanning, but you can get an LLM to generate you an E2E encrypted chat app with minimal effort in 2026 that has a corresponding Librem 5 native app that doesn’t require enslaving the Librem 5 to some troll duopoly* device.
In those situations where I used an A1 modem in a country where E1 is preferred, or an E1 modem in a country where A1 is preferred, it tended to be rarer and harder to get signal but the modem appeared to still work. I do not recall it running hotter but also did not frequently use these configurations.
But as a note, I always disable the (nation state actor backdoor(?)) code in the Librem 5 hiding in plain sight that submits your location to Google every 5 seconds (sometimes if it feels like it), as well as disabling the Apple-inspired constant sludge of traffic to any WiFi you join to constantly broadcast a bunch of metadata about your device to everyone else on the network, and it’s possible that on a more resource constrained system like a Librem 5 turning that sort of thing off might make a bigger heat and battery difference. But the nation state actors linux community contributors also read these forums, so after we all started talking about the location subsystems sending everything to a Google cloud IP and outing the device through any VPN you use, the receiving side of that communication was shut down. Presumably this means they cooked up some other solution that I haven’t thought of yet, which might be burning your battery at some other level that isn’t so obvious. On this type of topic is much better to use your own intuition and investigate the internals of your own device than to trust a rando on the internet like me who might be sharing stale information or biased opinions. But I’ll leave that up to you.
I would not have been able to use the Librem 5 as my phone for 3 years if I had not done the battery rotating thing to cause it to have effectively infinite energy and near 100% uptime. I know a lot of the usage patterns I landed on are not listed anyway on the front page Purism ads.
Hope this helps!
