Low Disk Space on Filesystem root

[ichbins]

Hello everybody,

I am trying to make a fresh install on my Pinephone, but it results in a device that is not booting anymore. I am flashing mobian-installer-pinephone-phosh-20220621.img to eMMC and the installation works as usual. After the installation I run apt update and apt upgrade and get this message in the status bar:

Low Disk Space on "Filesystem root"
The volume "Filesystem root" has only
166.3 MB disk space remaining.

The update process shows a littlebit later: No more disk space available.

Code:

cp: Fehler beim Schreiben von '/var/tmp/mkinitramfs_sbR54T//usr/lib/aarch64-linux-gnu/libharfbuzz.so.0.20704.0':
Auf dem Gerät ist kein Speicherplatz mehr verfügbar
ERROR: Couldn't copy /bin/osk-sdl
E: /usr/share/initramfs-tools/hooks/osk-sdl failed with return 1.
update-initramfs: failed for /boot/initrd.img-5.15-sunxi64 with 1.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
I: u-boot-menu: syncing /usr/lib/linux-image-5.15-sunxi64 to /boot/dtb-5.15-sunxi64
P: Checking for EXTLINUX directory... found.
P: Writing config for vmlinuz-5.15-sunxi64...
dpkg: Fehler beim Bearbeiten des Paketes linux-image-5.15-sunxi64 (--configure):
»installiertes post-installation-Skript des Paketes linux-image-5.15-sunxi64«-Unterprozess gab den Fehlerwert 1
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I never had this disk space problem before, when I made a fresh installation. How should I make the installation and update to get a working system?