$ ubuntu-device-flash touch --channel=ubuntu-touch/rc-proposed/meizu.en --bootstrap --recovery-image=recovery-arale.img 
2015/08/10 16:55:23 Expecting the device to be in the bootloader... waiting
2015/08/10 16:55:23 Device is |arale|
2015/08/10 16:55:24 Flashing version 83 from ubuntu-touch/rc-proposed/meizu.en channel and server https://system-image.ubuntu.com to device arale
1.48 MB / 60.83 MB [=>__________________________________________________________________________________________________________] 2.44 % 216.68 KB/s 4m40scan't flash recovery image