When kernel variants were renamed in https://gitlab.com/postmarketOS/pmaports/-/commit/69cd6ff843fa3173da8988dfbcc00ba5b18cb48f these dtb vars were forgotten, making it impossible to boot a kernel build with `pmbootstrap build linux-postmarketos-exynos4`, no dtb is appended to the zImage and we get stuck on samsungs boot logo.