Raw to qcow2 fails

hi all,
since raw images are not snapshotable, I need to convert them to qcow2.
I am facing an issue where if I shutdown a VM, look for its image (oneimage show xx), and run qemu-img convert -p -O qcow2 xxx xxx.qcow2 , then import the new qcow2 image (virtio / qcow2) as either an OS image or data block, the image is not bootable.

I noticed that the new qcow2 image is only 193Ko in size…

Any hint appreciated, thank you

any hint would be appreciated.