linux 修改img

先列出指定磁盘映像文件（DS918_7.2-64570.img）的分区信息

root@huangy:/home/huangy/QunHui# fdisk -l DS918_7.2-64570.img
Disk DS918_7.2-64570.img: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x16af7bb3

Device                           Boot  Start     End     Sectors  Size Id Type
DS918_7.2-64570.img1 *      2048  104447  102400   50M 83 Linux
DS918_7.2-64570.img2      104448  206847  102400   50M 83 Linux
DS918_7.2-64570.img3      206848 2097151 1890304  923M 83 Linux

若要挂载Device DS918_7.2-64570.img1
则需要计算出偏移量 start * Units，即 2048 * 512

mount -o loop,offset=1048576 /home/huangy/QunHui/DS918_7.2-64570.img /mnt/