老笔记本t400上装了两块硬盘，其中一块装了win7，另一块是数据盘，想体验一下双系统，想体验一下双系统，就在数据盘上划出70G的空间准备安装deepin。镜像是官网下载的20.6，用ventoy制作了启动盘。笔记本不支持UEFI，用legacy方式启动，硬盘也是mbr。

按照论坛教程，手动分了五个区，如图：

继续安装，一会就失败了，看日志应该是前面的“调整分区/dev/sdb2的大小“这部操作出错了“umount: /dev/sdb2: not mounted.”。这个sdb2是哪来的，前面手动分区的时候根本没出现。

umount: /dev/sdb2: not mounted.
[Debug  ] [  ] ResizeMovePartition() Partition: {
    path: "/dev/sdb2"
    number: 2
    fs: "unknown"
    type: "Extended"
    status: "Real"
    os: ""
    busy: false
    label: ""
    name: ""
    mount point: ""
    start: 75198464
    end: 625135615
    sector size: 512
    flags: (7)
    }

Error: Unable to satisfy all constraints on the partition.
[Error  ] [  ] ResizeMovePartition() failed: Partition: {
    path: "/dev/sdb2"
    number: 2
    fs: "unknown"
    type: "Extended"
    status: "Real"
    os: ""
    busy: false
    label: ""
    name: ""
    mount point: ""
    start: 75198464
    end: 625135615
    sector size: 512
    flags: (7)
    }