APF6 EMMC

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Revision as of 14:33, 21 January 2015 by JulienB (Talk | contribs) (User Data partition layout)

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APF6 eMMC layout

By default, the 4GB eMMC on APF6 board has 4 physical/hardware partitions:

Boot0 Boot1 RPMB User Data


Name U-Boot name Size Comment
boot0 mmc dev 0 1 2MBytes U-Boot is installed on this partition
boot1 mmc dev 0 2 2MBytes Not used
rpmb mmc dev 0 3 512KBytes Not used
User Data mmc dev 0 0 remaining space Kernel, device tree and rootfs

Boot0 partition layout

Offset (blocks) Offset (bytes) Comment
0 0
0x02 1 KB U-Boot SPL (apf6-u-boot.spl)
0x8a 69 KB U-Boot IMG (apf6-u-boot.img)
512 KB
1024 KB U-Boot environment
1536 KB Redundant U-Boot environment

User Data partition layout

There are two primary partitions on the "User Data" physical partition:

... Boot Rootfs


Name U-Boot device Linux device Offset (blocks) Size Comment
... NA NA 0 1 MBytes (2048 blocks) Free
Boot mmc 0:1 /dev/mmcblk2p1 2048 (0x800) 24 MBytes (49152 blocks) The kernel and the device tree (inside a dtbs/ directory) are on this partition (ext4 formatted)
Rootfs mmc 0:2 /dev/mmcblk2p2 (0x18800) Rest of space (<3816448 blocks) the rootfs is on this partition (ext4 formatted)
  • By default rootfs is only occupying the size of the .ext4 image flashed with U-Boot. If you want to increase the rootfs available free space then, after Linux has booted, use the following command:
# resize2fs /dev/mmcblk2p2

Rootfs will then be extended to all the "Rootfs" eMMC partition space.

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