User:Gdstr

	This user's main device is a Fairphone_4_(fairphone-fp4).

	This user's Nura GitLab profile is @gdstr.

	This user's Alpine GitLab profile is @gdstr.

	This user's freedesktop GitLab profile is @gdstr.

	This user's gitlab.gnome.org GitLab profile is @gdstr.

	This user's invent.kde.org GitLab profile is @gdstr.

	This user's salsa.debian.org GitLab profile is @gdstr.

	This user's Codeberg profile is @gdstr.

	This user is @gdstr on tchncs.de.

Computer science student at TU Dresden. Feel free to move any information on this page to a more appropriate place.

Owns Devices

Device	Notes
Apple iPhone 6 (apple-n61)
ASUS MeMO Pad FHD 10 (ME302C) (asus-redhookbay)	Android 4.3
Fairphone 4 (fairphone-fp4)	6/128 GB, postmarketOS, phosh, daily driver
Google Pixel 4a (google-sunfish)	pmOS, available for testing
Samsung Galaxy A5 2016 (samsung-a5xelte)	pmOS but boot loop

Flashing tips

• LIBUSB_ERROR_BUSY: try adb kill-server
• run pmbootstrap flashing command before connecting device via USB (command will wait for device)

samsung-a5xelte

• needs custom heimdall b/c of Benjamin-Dobell/Heimdall#347
• when to press which button when flashing recovery is very well documented in this (German) guide from Bits & Bäume Dresden: https://dresden.bits-und-baeume.org/artikel/2025-09-19-ds25-flash-a5-2016/#-recovery-flashen

google-sunfish

• pre-built image didn't work b/c Touchscreen is unavailable
  • either do https://wiki.postmarketos.org/wiki/SSH#Enable_SSH_in_downloaded_image or
  • use pmbootstrap

fairphone-fp4

• auto suspend breaks modem → disable auto suspend
• always waydroid session stop before shutdown / reboot to ensure it still starts after
• pmaports#2841 Wi-Fi is kinda broken, high latency, ping spikes, connection failures → use WWAN
• Bluetooth headset usage not possible (neither audio input nor audio output in any of the handset profiles)
• “Battery: partial” means percentage indicator is a bit unreliable, but OK for rough estimate
• pmaports#4660 SMS received while modem / SIM card is unlocked but user is not logged in will be lost
• calls show up / can be placed, but no audio (also see below)
• GNOME/calls#711 MMI doesn't work, running e.g. *#21# just shows “USSD” box doing nothing
• pamports#4583 hardware protection shutdowns are not avoided, phone will get too hot and then shutdown e.g. when compiling
• Kernel isn't built with the UVC driver, therefore USB cameras are unlikely to work
• adding a USB printer via GNOME settings doesn't work for some reason but works via ldadmin

Components not coming online after boot sometimes

• speaker
• gyroscope

Components that sometimes stop working while running

• Bluetooth

How-to: audio for calls of any kind (cellular, SIP, XMPP, Matrix, …)

• output: speaker, Bluetooth headset / microphone
• input: wired device with DAC: headset, microphone or adapter
  • also see the notes on USB peripherals above
  • most wired audio devices don't have a DAC, check your device / the device you want to buy really has it
  • personally, I've tested the following adapters, both work fine on the audio level
    • https://www.reichelt.com/de/en/shop/product/converter_usb-c_connector_to_3_5_mm_jack_socket_dac-334600 works fine
    • https://www.reichelt.com/de/en/shop/product/usb_type-c_cable_to_3_5_mm_audio_jack_adapter-337092 cover around the jack socket comes loose very fast

FP4: things that work just fine

• running USSD codes with Chatty
• (nearly) everything that does things with the USB-C port
  • network
  • keyboard, mouse, SD card adapter, …
  • headset
  • exception: HDMI / DP alternate mode
• vibration
• torch
• display brightness
• printing via CUPS/Gutenprint

Audio in calls: what works and what doesn't

Alice (A) is on postmarketOS, Bob (B) is on a system where everything works (e.g. Android).

Cellular via GNOME calls

• A cannot hear B, B cannot hear A

SIP via GNOME calls

• A can hear B, B can hear A

XMPP via Dino

• A can hear B, B cannot hear A

Matrix via nheko

• pmaports#4443 aports#18092
• A placing call fails without notice
• A receiving call from B shows “Voice Call” popup, trying to accept fails with toast “Missing GStreamer elements: webrtcbin”

Signal via Android app via Waydroid

• when A calls B, call will show up as missed immediately for some reason (problem with NAT traversal?)
• A can hear B, B can hear A

Signal via Signal Desktop

• A can hear B, B can hear A

Threema via Android app via Waydroid

• A can hear B, B can hear A

Linux on mobile support advocacy

Better UI support for mobile needed

• Thunderbird
• Firefox
• Gajim

Other

• Signal doesn't support usage without an Android or iOS system (without using unofficial software, e.g. signal-cli)
• TODO: Threema has a “Desktop” version but it cannot be used as it requires scanning a QR code from the Android app and Waydroid doesn't support passing image via the Android camera API whatsoever
• QField aarch64 AppImage build