EMMC OPOS6UL
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OPOS6UL eMMC layout
By default, the 4GB eMMC on OPOS6UL module has 4 physical/hardware partitions:
| Boot0 | Boot1 | RPMB | User Data |
| Name | U-Boot name | Size | Comment |
|---|---|---|---|
| boot0 | mmc dev 0 1 | 4MBytes | U-Boot is installed on this partition |
| boot1 | mmc dev 0 2 | 4MBytes | Not used |
| rpmb | mmc dev 0 3 | 512KBytes | Not used |
| User Data | mmc dev 0 0 | remaining space (~3,7GBytes) | Kernel, device tree and rootfs |
Boot0 partition layout
| . | SPL | IMG | ... | ENV1 | ... | ENV2 | ... |
- Linux device: /dev/mmcblk0boot0
| Offset (blocks) | Offset (bytes) | Size (bytes) | Comment |
|---|---|---|---|
| 0 | 0 | 1 KB (0x400) | Free |
| 0x02 | 1 KB (0x400) | 68 KB | U-Boot SPL (opos6ul-u-boot.spl) |
| 0x8a | 69 KB (0x11400) | 512 KB | U-Boot IMG (opos6ul-u-boot.img) |
| Free | |||
| 0x800 (2048) | 1024 KB (0x100000) | 10 KB (0x2800) | U-Boot environment |
| Free | |||
| 0xc00 (3072) | 1536 KB (0x180000) | 10 KB (0x2800) | Redundant U-Boot environment |
| Free |
Boot1 partition layout
- Not used !
RPMB partition layout
- Not used !
User Data partition layout
There are 3 partitions on the "User Data" physical partition:
| ... | Failsafe/Update (primary) | Default Rootfs (primary) | Home/Data (primary) |
| Name | U-Boot device | Linux device | Offset (bytes) | Offset (sectors/blocs) | Size | Comment |
|---|---|---|---|---|---|---|
| MBR | NA | NA | 0 | 0 | 512 bytes (1 block) | Master Boot Record + some spare space ( -> Don't touch it :-) ) |
| Failsafe | mmc 0:1 | /dev/mmcblk0p1 | 1M | 2048 (0x800) | 128MBytes (262144 sectors) | system/rootfs to restore your board in case of problem or setup a safe update mechanism (ext4 formatted) |
| Rootfs | mmc 0:2 | /dev/mmcblk0p2 | 264192 (0x40800) | 2GBytes (4194304 sectors) | the default booted rootfs is on this partition (ext4 formatted) | |
| Home/Data | mmc 0:3 | /dev/mmcblk0p3 | 4458496 (0x440800) | Rest of space: ~1,5GBytes (3176448 sectors) | HOME can be stored on this partition (ext4 formatted) |
- By default, when flashed from U-Boot, rootfs and boot are only occupying the size of the .ext4 images used during flashing. If you want to increase the rootfs/boot size to all available free space then, after Linux has booted, use the following commands:
# resize2fs /dev/mmcblk0p2 # for Rootfs
- Or with apf-config command:
# apf-config
- In menu:
| 1 Expand Filesystem(s) OS can then use all eMMC/SD space |
Rootfs/Boot will then be extended to all the "Rootfs"/"Boot" eMMC partitions space.
Tips
- Commands to partition User Data from fdisk on Host PC with U-Boot UMS. Check /dev/sdc is your OPOS6UL device otherwise you may destroy your PC partition table !!!:
$ sudo fdisk /dev/sdc n p 1 2048 +128M n p 2 264192 +2G n p 3 4458496 7634943 w $ sudo mkfs.ext4 -O ^64bit /dev/sdc1 $ sudo mkfs.ext4 -O ^64bit /dev/sdc2 $ sudo mkfs.ext4 -O ^64bit /dev/sdc3
