linux环境下，手动制作嵌入式设备sd启动卡
一、卸载sdb卡
bhj@ubuntu:~$ sudo umount /dev/sdb1
bhj@ubuntu:~$ sudo umount /dev/sdb2
bhj@ubuntu:~$
二、分区
bhj@ubuntu:~$ sudo fdisk /dev/sdb
Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
命令(输入 m 获取帮助)： p
Disk /dev/sdb: 3.7 GiB, 3965190144 bytes, 7744512 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: 0x4843c375
设备 启动 Start 末尾 扇区 Size Id 类型
/dev/sdb1 2048 1026048 1024001 500M c W95 FAT32 (LBA)
/dev/sdb2 1028096 7744511 6716416 3.2G 83 Linux
命令(输入 m 获取帮助)： d
分区号 (1,2, default 2): 1
Partition 1 has been deleted.
命令(输入 m 获取帮助)： d
Selected partition 2
Partition 2 has been deleted.
命令(输入 m 获取帮助)： 2
2: unknown command
命令(输入 m 获取帮助)： m
Help:
DOS (MBR)
a toggle a bootable flag
b edit nested BSD disklabel
c toggle the dos compatibility flag
Generic
d delete a partition
F list free unpartitioned space
l list known partition types
n add a new partition
p print the partition table
t change a partition type
v verify the partition table
i print information about a partition
Misc
m print this menu
u change display/entry units
x extra functionality (experts only)
Script
I load disk layout from sfdisk script file
O dump disk layout to sfdisk script file
Save & Exit
w write table to disk and exit
q quit without saving changes
Create a new label
g create a new empty GPT partition table
G create a new empty SGI (IRIX) partition table
o create a new empty DOS partition table
s create a new empty Sun partition table
命令(输入 m 获取帮助)： p
Disk /dev/sdb: 3.7 GiB, 3965190144 bytes, 7744512 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: 0x4843c375
命令(输入 m 获取帮助)： x
专家命令(输入 m 显示帮助)： h
磁头数 (1-256, default 122): 255
专家命令(输入 m 显示帮助)： s
扇区数 (1-63, default 62): 63
专家命令(输入 m 显示帮助)： c
柱面数 (1-1048576, default 482): 482
专家命令(输入 m 显示帮助)： r
命令(输入 m 获取帮助)： n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p
分区号 (1-4, default 1): 1
First sector (2048-7744511, default 2048): +1024000
Value out of range.
First sector (2048-7744511, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-7744511, default 7744511): +1024000 //注意！此处有加号
Created a new partition 1 of type 'Linux' and of size 500 MiB.
命令(输入 m 获取帮助)： t
Selected partition 1
Partition type (type L to list all types): c
Changed type of partition 'Linux' to 'W95 FAT32 (LBA)'.
命令(输入 m 获取帮助)： a //切换可引导标志，否则无法引导启动
Selected partition 1
The bootable flag on partition 1 is enabled now.
命令(输入 m 获取帮助)： n
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): p
分区号 (2-4, default 2): 2
First sector (1026049-7744511, default 1028096):
Last sector, +sectors or +size{K,M,G,T,P} (1028096-7744511, default 7744511):
Created a new partition 2 of type 'Linux' and of size 3.2 GiB.
命令(输入 m 获取帮助)： p
Disk /dev/sdb: 3.7 GiB, 3965190144 bytes, 7744512 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: 0x4843c375
设备 启动 Start 末尾 扇区 Size Id 类型
/dev/sdb1 * 2048 1026048 1024001 500M c W95 FAT32 (LBA)
/dev/sdb2 1028096 7744511 6716416 3.2G 83 Linux
命令(输入 m 获取帮助)： w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
三、格式化SD卡
bhj@ubuntu:~$ sudo mkfs.msdos -F 32 /dev/sdb
sdb sdb1 sdb2
bhj@ubuntu:~$ sudo mkfs.msdos -F 32 /dev/sdb
sdb sdb1 sdb2
bhj@ubuntu:~$ sudo mkfs.msdos -F 32 /dev/sdb1 -n FAT32
mkfs.fat 3.0.28 (2015-05-16)
到此创建Linux的启动SD卡完成，需要注意的一点是，有时需要重新再Windows下再次使用FAT32格式化第一个引导分区FAT32，才能成功引导Linux。（请不要使用快速格式化）