We need to update the base images because they didn’t include the libretech-keyring package. Those keyrings have expired causing the error you see.
You can fix it by manually installing the package:
wget https://deb.libre.computer/repo/pool/main/libr/libretech-keyring/libretech-keyring_2024.05.19_all.deb
sudo dpkg -i libretech-keyring_2024.05.19_all.deb
sudo apt update
We will update the base images to include this package by default.