On 22.09.2017 21:07, 慕 冬亮 wrote: > qemu-img create $IMG 5G > sudo mkfs.ext4 $IMG > qemu-system-x86_64 -kernel /boot/vmlinuz-4.12.0-1-amd64 -hda > qemu-stretch.img -append "root=/dev/sda1 single" You have created an image without any partition table, so root should point to /dev/sda. And, as Reco already wrote, initrd is needed for ext4. i will also recommend to use the stretch kernel and initrd to boot you image. best regards Ulf