Android/Linux Dual Boot

Summary

To dual boot pmOS you need a boot method and a way to store data. After selecting both and following the guide, you will have a working device with dual boot. For a lot of the methods, you will need pmbootstrap How to boot pmOS on an Android phone Booting with a computer This is the simplest option, but you will need a computer to boot pmOS. If used with an SD card to store data, then nothing is going to be modified on the phone. After entering fastboot mode on your phone, run pmbootstrap flasher boot to start pmOS. Recovery partition WARNING: Doing this will make you lose the Android recovery mode, and will overwrite any recovery OS/software installed on the recovery partition(e.g. TWRP) If the pmOS kernel is written to the recovery partition, then your device will boot into pmOS when you enter recovery mode. You can get the image of the kernel by running pmbootstrap export. And fastboot flash recovery /tmp/postmarketOS-export/boot.img to flash it to recovery. Under this method, you would require to find a way to store pmOS because userdata is used by Android (However, you can share userdata between pmOS and android with #Stowaway). A/B slots On phones that have A/B slots, you can flash pmOS to system partition of slot B, and leave slot A and userdata for Android. If you want a bigger partition for pmOS, Please refer to #Custom Partition. Switching slots can be done with a computer using fastboot --set-active=[a/b] while the phone is in fastboot mode. Alternatively, you can use any of the following android apps to switch to pmOS: On pmOS you can use qbootctl to switch back to Android. U-boot U-Boot_porting#Implement_multiboot_involving_Android_in_a_device_aport On the Nokia N900 and other devices that use U-boot (like MangoPi MQ-Pro (mangopi-mq-pro), Xunlong Orange Pi 3 (xunlong-orangepi3)), U-boot provides a mechanism to select the OS. See Nokia N900#Installation and bootmenu on U-boot doc On some Amlogic devices with U-boot, there is a multi-boot mode: Amlogic#Bo...