Batocera and KNULLI write the image name, not the board, to the card's board file (post-image-script.sh). The target scraper now records each board's images from Config.in, the target lists carry them, and the installer maps a card's image to its board. KNULLI's boot/knulli.board is read too.
KNULLI builds per board on Batocera's Kconfig model from its own tree (knulli-cfw/knulli-linux at the tag platforms/knulli.yml pins): configs/knulli-*.board, package/system/knulli-system/Config.in, knulli-es-system/es_systems.yml and the knulli-cfw/buildroot submodule. Ten boards, the armhf library builds excluded.