But even for a phone from 2015 there were many models on the market, I don't expect every brands poured that much money in developing a phone.
What justifies such a big budget? And what could be a minimal budget for a decent phone?
By decent I mean an average phone: can run most of basic apps, average battery life and pictures quality.
I just did a brief frontend job for a smart-top device, so take this with a grain of salt, but basically when you're planning to release a cheap mobile phone (It was very common until a few years ago to find weird in-house phone brands in European supermarkets) you mainly license a SoC and some sort of development platform from a foundry and that's it.
Most drivers, radio devices, kernel, android releases are those you get at the beginning, you can't really change a thing due to them being closed source or just one step above from being a firmware blob with a few kernel hooks and once your contract expires your devices die with it.
We investigated if we could at least maintain the software on our own (so to not tell some telco clients their streaming devices were gonna die after 4 years) but it was a big fat no from the licensees. And reverse engineering what we already had was forbidden by contract.
In other words, if you want yo build a free phone, you need to build a free radio, a free storage solution, thousands of weird DACs, graphic cards, screen controllers, sensors and whatnot. Making sure you're not infringing on some patents. It's like starting from ground-up. And it's expensive.
A possible solution would be to invest into building into a raspberry-pi binary compatible base platform (and take advantage of their already open sourced drivers), but it was 100% economically unfeasible for a 100-200€ device.
If you design the HW yourself you suddenly need a vastly larger development budget. It's not like x86 stuff where the interfaces have been pretty open since the days of the original IBM PC.
Apple acquired Intels already existing cellular modem business in 2019 and just this year started shipping its own cellular modem and only on low end phones.
If you design the hardware, who are you going to get to manufacture it? How are you going to get TSMC to commit to a low volume?
Is there any other way than going through reverse engineering? Projects like LineageOS and others have shown this is really hard.
Why not simply start from scratch and make a truly open source phone? That is, design and build the electronics and the OS that goes on top of it. A bit like an iPhone+iOS but fully open source. Is this dream really unreachable?
I very much like the advice about using a file encryption tool like Cryptomator and then uploading the files to a mainstream cloud provider.
For instance, on Joplin my notes are encrypted and uploaded to dropbox, it works like a charm even on smartphone.
