我已经完成了所有命令，但加载仍在继续。似乎我在安装过程中遇到了错误
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
02288e089196d0c7 offline
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
02288e089196d0c7 offline
hanafi81@hanafi81 ~ $ adb reboot bootloader
error: device offline
hanafi81@hanafi81 ~ $ ./adb sideload
bash: ./adb: No such file or directory
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
02288e089196d0c7 offline
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ ./adb sideload
bash: ./adb: No such file or directory
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
02288e089196d0c7 sideload
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
hanafi81@hanafi81 ~ $ adb devices
List of devices attached
02288e089196d0c7 recovery
hanafi81@hanafi81 ~ $ ubuntu-device-flash --list-channels
devel-proposed (alias to ubuntu-touch/utopic-proposed)
devel-proposed-customized (alias to ubuntu-touch/utopic-proposed-customized)
ubuntu-touch/saucy
ubuntu-touch/saucy-customized
ubuntu-touch/trusty
ubuntu-touch/trusty-customized
ubuntu-touch/utopic-proposed-customized-generic
devel (alias to ubuntu-touch/utopic)
devel-customized-generic (alias to ubuntu-touch/utopic-customized-generic)
trusty-proposed-customized-demo
ubuntu-touch/saucy-proposed-customized
ubuntu-touch/saucy-surfaceflinger
ubuntu-touch/trusty-proposed-customized
ubuntu-touch/utopic-customized
saucy
saucy-customized
trusty
trusty-customized
ubuntu-touch/devel-proposed (alias to ubuntu-touch/utopic-proposed)
ubuntu-touch/devel-proposed-customized (alias to ubuntu-touch/utopic-proposed-customized)
ubuntu-touch/utopic-proposed-customized-demo
saucy-proposed-customized
saucy-surfaceflinger
trusty-proposed-customized
ubuntu-touch/devel (alias to ubuntu-touch/utopic)
ubuntu-touch/devel-customized-generic (alias to ubuntu-touch/utopic-customized-generic)
ubuntu-touch/trusty-proposed-customized-demo
ubuntu-touch/utopic-customized-demo
devel-proposed-customized-generic (alias to ubuntu-touch/utopic-proposed-customized-generic)
trusty-customized-demo
ubuntu-touch/devel-proposed-customized-demo (alias to ubuntu-touch/utopic-proposed-customized-demo)
ubuntu-touch/stable (alias to ubuntu-touch/stable)
ubuntu-touch/trusty-customized-generic
ubuntu-touch/utopic-proposed
ubuntu-touch/utopic-proposed-customized
devel-customized (alias to ubuntu-touch/utopic-customized)
ubuntu-touch/devel-customized-demo (alias to ubuntu-touch/utopic-customized-demo)
ubuntu-touch/saucy-proposed
ubuntu-touch/trusty-proposed
ubuntu-touch/trusty-proposed-customized-generic
ubuntu-touch/utopic
ubuntu-touch/utopic-customized-generic
stable (alias to ubuntu-touch/stable)
trusty-customized-generic
ubuntu-touch/devel-proposed-customized-generic (alias to ubuntu-touch/utopic-proposed-customized-generic)
ubuntu-touch/trusty-customized-demo
saucy-proposed
trusty-proposed
trusty-proposed-customized-generic
ubuntu-touch/devel-customized (alias to ubuntu-touch/utopic-customized)
hanafi81@hanafi81 ~ $ ubuntu-device-flash --channel=devel-proposed
2014/06/12 18:33:13 Expecting the device to expose an adb interface...
2014/06/12 18:33:13 Device is |mako|
2014/06/12 18:33:16 Flashing version 79 from devel-proposed channel and server https://system-image.ubuntu.com to device mako
2014/06/12 18:33:16 ubuntu-touch/utopic-proposed is a channel alias to devel-proposed
2014/06/12 18:33:21 Start pushing /home/hanafi81/.cache/ubuntuimages/pool/device-8e3e30aa503cbe9b6fdf3497ad5cf38398f8bcf88c80d98a988a4ad464b3db28.tar.xz to device
2014/06/12 18:33:21 Start pushing /home/hanafi81/.cache/ubuntuimages/ubuntu-touch/devel-proposed/mako/version-79.tar.xz to device
2014/06/12 18:33:21 Start pushing /home/hanafi81/.cache/ubuntuimages/gpg/image-signing.tar.xz to device
2014/06/12 18:33:21 Start pushing /home/hanafi81/.cache/ubuntuimages/gpg/image-master.tar.xz to device
224.00 KB / 334.17 MB [_______________________________] 0.07 % 983.71 KB/s 5m47s2014/06/12 18:33:21 Done pushing /home/hanafi81/.cache/ubuntuimages/gpg/image-signing.tar.xz to device
2014/06/12 18:33:21 Done pushing /home/hanafi81/.cache/ubuntuimages/ubuntu-touch/devel-proposed/mako/version-79.tar.xz to device
2014/06/12 18:33:21 Done pushing /home/hanafi81/.cache/ubuntuimages/gpg/image-master.tar.xz to device
2.05 MB / 334.17 MB [________________________________] 0.61 % 208.21 KB/s 27m13s2014/06/12 18:33:31 Done pushing /home/hanafi81/.cache/ubuntuimages/pool/device-8e3e30aa503cbe9b6fdf3497ad5cf38398f8bcf88c80d98a988a4ad464b3db28.tar.xz to device
334.17 MB / 334.17 MB [====================================] 100.00 % 1.07 MB/s
2014/06/12 18:38:33 Start pushing /home/hanafi81/.cache/ubuntuimages/pool/ubuntu-473f9aa1f2618d7eee30e116491b01ec5815baa7b9a7b7c02afb88896c15f041.tar.xz to device
2014/06/12 18:39:50 Done pushing /home/hanafi81/.cache/ubuntuimages/pool/ubuntu-473f9aa1f2618d7eee30e116491b01ec5815baa7b9a7b7c02afb88896c15f041.tar.xz to device
2014/06/12 18:39:50 Created ubuntu_command: /home/hanafi81/.cache/ubuntuimages/ubuntu_commands665141130
2014/06/12 18:39:50 Rebooting into recovery to flash
答案1
经过多次尝试，安装成功。我重新启动 adb start-server，清除缓存和出厂设置。最后，我按照 ubuntu wiki 中的说明开始安装过程。安装完成。
答案2
昨天，我在 Nexus 4（运行 Stock Android 4.4.3）上以双启动模式安装了 Ubuntu Touch，这样当我不在摆弄 Ubuntu Touch 时，就可以随时切换回 Android。
值得一看。https://wiki.ubuntu.com/Touch/DualBootInstallation
hanafi81@hanafi81 ~ $ adb reboot bootloader
error: device offline
当您未启用 Android 调试时可能会发生这种情况。
在您的设备上启用 USB 调试。
在大多数运行 Android 3.2 或更早版本的设备上，您可以在“设置”>“应用程序”>“开发”下找到该选项。
在 Android 4.0 及更新版本中，它位于“设置”>“开发者选项”中。
注意：在 Android 4.2 及更高版本中，开发者选项默认处于隐藏状态。要启用该选项，请转到“设置”>“关于手机”，然后点按版本号七次。返回上一屏幕以查找开发者选项。