Raspberry Pi 4 and balena x86 players no longer get stuck on the boot splash

If your Raspberry Pi 4, or an x86 PC set up from the balena image, started up to the Anthias splash screen and never got as far as your content, Anthias 2026.05.2 fixes it. You only need to do something if you run your own balena fleet; the settings to check are below.

The 2 boards had different causes.

x86 on balena

On an x86 PC running the balena image, the screen stayed on the splash while the viewer's logs filled with lines like Could not make device fd drm master and Swapchain for output 'DP-1' failed test. balenaOS leaves the boot splash (Plymouth) running, and on x86 it kept hold of the display. The viewer now closes the splash before it starts. Installs on Debian aren't affected, since the splash has already closed there by the time the viewer starts.

If you deploy to your own balena fleet from a compose file you maintain, the anthias-viewer service needs 2 additions for this: the environment variable DBUS_SYSTEM_BUS_ADDRESS=unix:path=/host/run/dbus/system_bus_socket and the label io.balena.features.dbus: '1'. docker-compose.balena.yml.tmpl in the repository has both.

Raspberry Pi 4

In Anthias 2026.05.1, a Raspberry Pi 4 could stay on the splash for 2 reasons.

On some boots, the viewer opened the graphics device that has no display attached (/dev/dri/card1 when the display was on card0), found no screen, and never started. This happened on Raspberry Pi OS installs as well as on balena. The viewer now looks for the device with the display connector every time it starts, and logs its choice, for example start_viewer: eglfs DRM device = /dev/dri/card0.

On the official Pi 4 balena fleet, the setting that loads the full KMS graphics driver was stored with literal quotes, as "vc4-kms-v3d". The firmware couldn't read it, so the driver didn't load and the viewer couldn't start. The fleet setting is now vc4-kms-v3d, without quotes, and devices on the fleet restart once to pick it up. If you run your own Pi 4 fleet, check that BALENA_HOST_CONFIG_dtoverlay (or the older RESIN_HOST_CONFIG_dtoverlay) is vc4-kms-v3d with no quotes around it.