In my case, after setup wizard in first boot, system hang-up with failed message:
[FAILED] Failed to start oem-config.service.
See "systemctl status oem-config.service" for details.
Anyway, the system still can run after power-off and re-boot again.
Download Ubuntu MATE for the Raspberry Pi 2 (2015-04-22 version)
Boot-up Ubuntu MATE 15.04 for the Raspberry Pi 2 (2015-04-22 version)
To write the img on microSD, ddrescue is needed. To install ddrescue on Ubuntu, enter the command:
$ sudo apt-get install gddrescue