ogra@styx:~/all-snaps/amd64$ sudo ../ubuntu-device-flash core rolling --channel edge --os livecd.ubuntu-core.os.snap --kernel livecd.ubuntu-core.kernel.snap --gadget canonical-pc.canonical -o test.img
[sudo] Passwort für ogra: 
Determining gadget configuration
40.00 KB / 40.00 KB [========================================================================] 100.00 % 479.44 KB/s 0
Installing canonical-pc.canonical
40.00 KB / 40.00 KB [========================================================================] 100.00 % 466.54 KB/s 0
Installing livecd.ubuntu-core.kernel.snap
Installing livecd.ubuntu-core.os.snap
Removing unneeded: /tmp/diskimage192919562/boot/EFI/ubuntu/grub/canonical-pc-linux.sideload_IORYKBHcPRNU.snap
New image complete
Summary:
 Output: test.img
 Architecture: amd64
 Channel: edge
 Version: 0
ogra@styx:~/all-snaps/amd64$