The eMMC (internal memory of the device) is split into four physical partitions to perform the various functions of the device:

  • BOOT 1: This partition contains the U-Boot bootloader image that is executed when the device is powered on. It starts the installed operating system and allows some device configurations.

  • BOOT 2: Contains the U-Boot environment and its redundant copy.

  • RPMB: This is the replay-protected memory-block partition, used to manage data in an authenticated and replay-protected manner. It is not currently in use.

  • User Data: Holds the operating system. It’s divided into logical partitions.

Standard partition table

eMMC layout

The default partition table for the user data area has the following partitions:

  • linux: Contains the Linux kernel, device tree files, and U-Boot boot scripts. U-Boot reads the operating system files from this default partition.

  • recovery: Serves as a placeholder for a recovery Linux ramdisk image that can be launched (instead of the default operating system) to perform firmware updates on the device.

  • rootfs: Linux root file system partition.

  • update: Serves as a placeholder partition to store firmware update files prior to launching a firmware update process on the device.

  • safe/safe2: Contains the encryption key for encrypted partitions. See the TrustFence documentation for more information on encrypted partitions.

  • data: Serves as a placeholder partition for storing user data.

Dual boot partition table

eMMC layout for dual boot

On a dual boot-enabled system (see Prepare your target for dual boot) the user data area has the following partitions:

  • linux_a: Contains the Linux kernel, device tree files, and U-Boot boot scripts. U-Boot reads the operating system files from this default partition.

  • linux_b: Same as linux_a (for system B).

  • rootfs_a: Linux root file system partition (for system A)

  • rootfs_b: Linux root file system partition (for system B)

  • safe/safe2: Contains the encryption key for encrypted partitions. See the TrustFence documentation for more information on encrypted partitions.

  • data: Empty placeholder partition for storing user data.