该设备是 Nexus 4，目前运行的是 Android 4.4.4，不过我已经尝试过 5.0.1。我正在使用http://developer.ubuntu.com/en/start/ubuntu-for-devices/installing-ubuntu-for-devices/上的说明在Nexus 4 上安装 Ubuntu Touch（开发频道），单启动. 一切都按预期运行，直到我运行
$ ubuntu-device-flash --channel=devel --bootstrap
DEPRECATED: Implicit 'touch' subcommand assumed
2015/02/06 15:14:06 Expecting the device to be in the bootloader... waiting
2015/02/06 15:14:06 Device is |mako|
2015/02/06 15:14:06 Flashing version 1 from devel channel and server https://system-image.ubuntu.com to device mako
3.67 MB / 3.67 MB [=======================================================] 100.00 % 1.34 MB/s
44.77 MB / 44.77 MB [=====================================================] 100.00 % 1.83 MB/s
321.82 MB / 321.82 MB [===================================================] 100.00 % …