https://buildd.debian.org/status/logs.php?pkg=linux&arch=loong64 zstd is not installed when building. The other architectures have CONFIG_KERNEL_ZSTD=n CONFIG_KERNEL_ZSTD is enabled upstream: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/loongarch/configs/loongson3_defconfig#n2