Tips and tricks

SSH Config

When postmarketOS is reinstalled, a new ssh host key will be generated. Your SSH client will detect this, and refuse to connect, requiring you to run ssh-keygen -R 172.16.42.1 each time a new host key is generated.

To disable this check, and to allow you to connect by running ssh postmarketos, add the following to your ~/.ssh/config:

Host postmarketos
    HostName 172.16.42.1
    StrictHostKeyChecking no
    UserKnownHostsFile=/dev/null

Warning: Ignoring host keys could leave you vulnerable to a Man-in-the-middle attack

SSH with Suckless Terminal

When you ssh into postmarktetos using the suckless terminal (st) on your host, you will get errors with vim:

E558: Terminal entry not found in terminfo
'st' not known. Available builtin terminals are:
    builtin_amiga

Furthermore, gpg will refuse to decrypt files and return the following error:

gpg: public key decryption failed: Required environment variable not set
gpg: decryption failed: No secret key

To fix, simply add export TERM=xterm to your ~/.profile file on your postmarketos phone.

Some interesting ideas

Here are some interesting ideas that you can do with your device with postmarketOS

Use it as a mini retro handheld gaming device. As there are many good retro emulators that can make your device one great gaming device.
Use it as a mini penetration testing device. As postmarketOS is a pure linux os, you can run Wireshark and other penetration testing software with it.
You can run full Desktop Environment, with Inkscape, GIMP and full desktop browser with extensions in your device, .

VNC

Using x11vnc, which is in the Alpine repos. You need a running X server (e.g. running Xfce), then you just run x11vnc on the device in a terminal/tty and connect to it. From there, you can manipulate the previously running X server. You might need to specify the X server if x11vnc does not detect it (e.g. by passing -display :0 to it or doing a export DISPLAY=:0 before running it, assuming the display is at :0)

Update the architecture of your device

Some devices have the armhf-architecture but the device supports armv7/aarch64. Some packages can not be built for armhf, so it is useful to update the architecture.

While updating armhf -> armv7 is usually trivial, armhf/armv7 -> aarch64 is usually not. See here

from armhf to armv7

Update the architecture in the following files:

device/testing/device-wiki-example/APKBUILD
device/testing/device-wiki-example/deviceinfo
device/testing/linux-wiki-example/APKBUILD
device/testing/firmware-wiki-example/APKBUILD

Update the name of the config-wiki-example.armhf in device/linux-wiki-example to config-wiki-example.armv7

Create new checksums for the device package pmbootstrap checksum device-wiki-example as well as for the kernel package pmbootstrap checksum linux-wiki-example, pmbootstrap zap, and reinstall.

Due to CI-Updates in the Gitlab-repository it may be necessary to also modernize your aport before you can upstream your work.

Misc

The splash screen is highly configurable (scroll down for an example)!
Browse the Linux source with links to all references here
Qualcomm and maybe some other Androids can simply reboot from postmarketOS (or any Linux distro) into your bootloader or recovery with reboot -f bootloader and reboot -f recovery
Battery capacity can be monitored to trigger low battery actions. See Battery capacity monitoring for more information.

Copy a port

If you know a port of another device works on your device too, you can copy the port.

Reasons for copying a port:

You cannot make your device boot yourself, or you want to save the time it takes to do it
There are no kernel sources available for your device
The devices are very similar (e.g. same SoC), but need small adjustments

Keep in mind that if you copy a port, you copy all the problems and bugs as well. For example, it can be better to create a new up-to-date port than to copy a port which only compiles under gcc6 and still uses armhf.

If you want to copy the port of a device, copy all the files of the device in your device-folder and rename them to the new ones. Then simply follow the porting guide. If the config-file of your new device is available, try to use it instead of the old one.