2

Why so many mmcblk devices?

/dev/block/mmcblk0
/dev/block/mmcblk0boot0
/dev/block/mmcblk0boot1
/dev/block/mmcblk0p1
/dev/block/mmcblk0p10
/dev/block/mmcblk0p11
/dev/block/mmcblk0p12
/dev/block/mmcblk0p13
/dev/block/mmcblk0p14
/dev/block/mmcblk0p15
/dev/block/mmcblk0p16
/dev/block/mmcblk0p17
/dev/block/mmcblk0p18
/dev/block/mmcblk0p19
/dev/block/mmcblk0p2
/dev/block/mmcblk0p20
/dev/block/mmcblk0p21
/dev/block/mmcblk0p3
/dev/block/mmcblk0p4
/dev/block/mmcblk0p5
/dev/block/mmcblk0p6
/dev/block/mmcblk0p7
/dev/block/mmcblk0p8
/dev/block/mmcblk0p9
/dev/block/mmcblk0rpmb

What is the normal amount of mmcblk devices? I'm having problems booting and I'm wondering if this kind of formatting is normal or not?

When I boot up under TWRP, and adb in. After I run mount -a, I get

/dev/block/mmcblk0p19 on /cache type ext4 (rw,seclabel,relatime,data=ordered)
/dev/block/mmcblk0p21 on /data type ext4 (rw,seclabel,relatime,data=ordered)
/dev/block/mmcblk0p20 on /system type ext4 (rw,seclabel,relatime)
/dev/block/mmcblk0p16 on /preload type ext4 (rw,seclabel,relatime,data=ordered)

That only explains four of them though.

6

There is nothing abnormal in this case. They is only one device in the first preformatted text, which is /dev/block/mmcblk0 (just like /dev/sda in Linux distros). The rest are the partitions within that device (akin to /dev/sda1, /dev/sda2 and so on).

There is no normal limit, not that I came across, for how many partitions a device can have. It depends upon how developers want to design and provide a functionality. E.g. earlier, there used to be one system and boot partition. But recent Android versions started a new normal of setting up additional boot and system partitions for fail-safe measures.

Also, mount command only shows the partition which are mounted under /. Some partitions are never needed to be mounted, such as ones concerning bootloader, so you won't see them in mount's output.

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.