$ sudo ubuntu-device-flash core --developer-mode --channel=edge -o /srv/vm/snappy.img rolling
Determining oem configuration
Starting download of generic-amd64
40.93 KB / 40.93 KB [================================================================================] 100.00 % 439.22 KB/s 
Done
operation not supported
2015/06/09 11:53:46 Warning: failed to remove /tmp/oem512010447/oem/generic-amd64/1.1.1: %!s(<nil>)
2015-06-09 09:53:46 ERROR snappy logger.go:199 generic-amd64 failed to install: unpack /tmp/generic-amd64547684322 to /tmp/oem512010447/oem/generic-amd64/1.1.1 failed with exit status 1
generic-amd64 failed to install: unpack /tmp/generic-amd64547684322 to /tmp/oem512010447/oem/generic-amd64/1.1.1 failed with exit status 1