lsblk查看分区：
<pre>
sdb      8:16   1   3.7G  0 disk
├─sdb1   8:17   1    16M  0 part   # boot
├─sdb2   8:18   1   700M  0 part   # root fs
├─sdb3   8:19   1    60M  0 part   # recover
├─sdb4   8:20   1     1K  0 part   # nothiing, ext partition
├─sdb5   8:21   1   350M  0 part   # db/other vars
├─sdb6   8:22   1   250M  0 part   # user space
└─sdb7   8:23   1   2.3G  0 part   # /media
</pre>

== create sd partition ==
create sd partition, we use kpartx and fdisk tool

=== use kpartx ===
==== install required packages (on x86) ====
 apt-get install kpartx

== mount mmc disk to test ==
===test mount mmc disk image from x86===
20140218.1828_image.img已经包含分区表信息
 kpartx -av /var/www/luna-client-images/20140218.1828_image.img
 mount /dev/mapper/loop0p1 /mnt

完成测试后，正确卸载
 umount /mnt
 kpartx -d /dev/loop0