Probably this hard: https://postmarketos.org/

Linux is just the Kernel, Android is the OS. There's a ton of stuff on top of Linux that makes an Android device.

Making an Android device (or Android device hardware) run Linux isn't hard. In fact, you can just use Termux on pretty much any Android device to run a regular desktop Linux distro run in a container on Android. That way, the Linux distro uses the kernel from the host Android OS and just runs its own userspace parallel to Android's userspace.

But if you want to make a stand-alone Linux phone without Android, your biggest issue is that you won't have phone apps. There's close to no app support for phone-linux. So on your Linux phone you won't get any banking/authenticator/messaging/games/... apps. You can run desktop apps, but that sucks on a tiny touchscreen display. And many use cases (e.g. authenticator/two-factor/buying public transport tickets) are very cumbersome or sometimes even not possible on desktop OSes.

Now you an make your Linux phone run Android by emulating the Android userspace. That's possible, but then again you are basically running Android at that point anyway. But Android with one big caveat: It's not a Google Play Store Certified device, and it will never be if it's not running full Android.

And missing Google Play Store Certification means no google services and no apps that rely on Google Services or require Google Play Store Certification. That means e.g. no Banking/Authenticator apps and many games won't run.

Also, if you aren't actually running Android but some kind of Android emulator, you will always be outdated and buggy.

So essentially you made a phone that

• Runs Linux apps a little better than an Android phone
• Gives you more control
• Allows you to do much, much less in regards to it being an Android phone

People have done it. There are a handful of Linux phones (e.g. Librem 5, Pinephone) that are barely usable as phones due to lack of app support.

They've done the opposite as well, so running Linux on a phone originally designed for Android (e.g. PostmarketOS), also barely usable as a phone.

There's also the middle-ground with custom ROMs, some of them degoogled (like LineageOS, GrapheneOS, /e/ and many others). They run full-fat Android, but without all the Google apps including Play Store, Google Services and of course also without Google Play Store Certification. That's more usable as a phone, but you will still be cut off from anything using Google Services. There are some hacks and workarounds that sometimes work and sometimes not. You might get stuff to work but it's a constant race.

The problem is that currently if you want to use a phone as a full phone that covers all phone usecases, it's got to be an iPhone or a Google certified Android phone.

You can, but no one will use it because you won't have Android apps on it. The lock in is real

https://puri.sm/products/librem-5-usa/

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