Fedora + arm guestfish: no operating system was found on this disk error - Solved

I thought of trying ARM based Fedora using emulation platform:

tried this command :
virt-copy-out -a Fedora-XFCE-armhfp-20-Alpha-4-sda.raw  /boot .

got this erorr:
guestfish: no operating system was found on this disk


Thanks libguestfs author , libguestfs which I used is very OLD.
So I tried using another command which he informed about.
guestfish --ro -a Fedora-XFCE-armhfp-20-Alpha-4-sda.raw -m /dev/sda1 tar-out / boot_simple.tar

This worked out. Thanks to rwmjones !