sudo ubuntu-device-flash --verbose core 15.04 --channel edge -o output.img
Determining oem configuration
Starting download of generic-amd64
40.94 KB / 40.94 KB [====================================================================================] 100.00 % 171.06 KB/s 
Done
Fetching information from server...
Downloading and setting up...
Download finished for /home/asac/.cache/ubuntuimages/ubuntu-core/15.04/edge/generic_amd64/version-8.tar.xz
38.62 MB / 38.62 MB [======================================================================================] 100.00 % 1.95 MB/s 
Download finished for /home/asac/.cache/ubuntuimages/pool/ubuntu-6de0c022a5873b9515ea80a71243c61d38f2d03fe8ed57315386a1dc10d796ba.tar.xz
95.82 MB / 95.82 MB [======================================================================================] 100.00 % 2.79 MB/s 
Searching for hardware.yaml in device part
Download finished for /home/asac/.cache/ubuntuimages/pool/device-896a3bf01c24d6202aed56ff52dab4cc38b924c7b6d14aaece04ab4a57bf2511.tar.xz
Partitioning...
Mapping...
Formatting...
Mapping...
Mounting...
Provisioning...
Installing generic-amd64
Starting download of generic-amd64
40.94 KB / 40.94 KB [====================================================================================] 100.00 % 550.19 KB/s 
Done
Unmounting...
Unmapping...
New image complete
Summary:
 Output: output.img
 Architecture: amd64
 Channel: edge
 Version: 8
Launch by running: kvm -m 768 output.img
asac@bigos:/tmp$ kvm -m 768 output.img