Raspberry Pi 2 and Pi 3 viewers retry a crashed start, and other fixes

A Raspberry Pi 4 with no display attached waits for one on balenaOS 2026.x, and device logs on every board no longer fill up with Qt debug output.

June 2, 2026

Fixes

On a Raspberry Pi 2 or Pi 3, the viewer often crashed while starting, with malloc(): unaligned tcache chunk detected in the log, and the container restarted in a loop. The viewer now retries the launch itself with a growing delay, up to 30 times at startup, and 3 times when it has to relaunch while content is playing, so playback doesn't stall for minutes. That gets many players going, but on some the crash happens on every launch and the screen stays dark. Anthias 2026.07.2 fixes the crash itself.
A Raspberry Pi 4 with no display attached could still crash-loop with no screens available on balenaOS 2026.x, despite the wait added in 2026.06.0. A virtual output that is always present was counted as a connected screen. It's ignored now, so the Pi 4 waits for a real display.
On x86, Raspberry Pi 5 and generic arm64 boards, the viewer no longer logs A configure is scheduled for an uninitialized xdg_surface when it starts.

Device logs are much easier to read. The viewer image no longer turns on Qt debug logging, which had been adding many lines a second to the logs on every board.

The C++ viewer tests run with QT_QUICK_BACKEND=software, so the video scene loads on hosts without a usable OpenGL context.
The Qt 6 viewer images install qt6-declarative-dev and the qml6-module-qtquick and qml6-module-qtmultimedia runtime modules, and no longer install libqt6multimediawidgets6. The QML modules aren't linked at build time, so a build without them succeeds, and the viewer then exits at startup with VideoView: QML video scene unavailable in its log.
The Pi 2 and Pi 3 viewer image installs gstreamer1.0-tools and the gstreamer1.0-plugins-base, -plugins-good, -plugins-bad and gstreamer1.0-alsa packages in place of vlc, and python-vlc is gone from the Python dependencies.
docs/board-enablement.md documents the Pi 2 and Pi 3 video path, the startup crash on the 32-bit viewer and the launch retries, and the new Pi 4 and Pi 5 video path.