1 解決 VirtualBox裏Ubuntu的共享文件夾無法訪問 之問題
sudo usermod -a -G vboxsf xxx（替換爲用戶名）
設置完後重啓
原文標題：You do not have the permissions necessary to view the contents of ‘shared_folder’
原文鏈接：http://darrenma.wordpress.com/2012/07/18/you-do-not-have-the-permissions-necessary-to-view-the-contents-of-shared_folder/
2 更新阿里源（Ubuntu16.04）
https://blog.csdn.net/qq_38038143/article/details/82978836
1.備份文件
sudo cp /etc/apt/sources.list /etc/apt/sources.list.old
2.打開文件
sudo gedit /etc/apt/sources.list
刪除原內容後，在文件中添加以下內容：
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu xenial partner
deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse
3.保存退出後，執行命令
sudo apt-get update
sudo apt-get upgrade
3 編譯環境搭建（可選）
1 https://blog.csdn.net/karaskass/article/details/102459757
2 sudo apt-get install u-boot-tools