The linux partition contains the following elements:
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The kernel binary.
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Several device tree blobs for each SOM and carrier board variant.
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A U-Boot bootscript to boot the system.
The main purpose of the bootscript is to select the appropriate device tree blob and overlays depending on the detected SOM variant and carrier board. This element is provided by the bootloader Digi Embedded Yocto recipe, not the kernel.
The linux partition is formatted in FAT file system.
Update files from U-Boot
To list the contents of the linux partition on MMC media, run ls mmc x:y in the U-Boot console where x is the device index (starting at 0) and y is the partition index (starting at 1). For example:
=> ls mmc 0:1 5721120 zimage-ccimx6sbc.bin 49226 zimage-imx6dl-ccimx6sbc.dtb 49405 zimage-imx6dl-ccimx6sbc-w.dtb 49492 zimage-imx6dl-ccimx6sbc-wb.dtb 51877 zimage-imx6q-ccimx6sbc.dtb 52052 zimage-imx6q-ccimx6sbc-w.dtb 52139 zimage-imx6q-ccimx6sbc-wb.dtb 52335 zimage-imx6q-ccimx6sbc-wb-ldo-bypass.dtb 52073 zimage-imx6q-ccimx6sbc-id129.dtb 52147 zimage-imx6q-ccimx6sbc-id130.dtb 49474 zimage-imx6dl-ccimx6sbc-id131.dtb 2336 boot.scr 12 file(s), 0 dir(s
To update the files from U-Boot console, run updatefile command. See Update files within partition.
Update files from Linux
The linux partition is automatically mounted to /mnt/linux, but as a read-only filesystem.
To list the contents of the linux partition:
~# ls -l /mnt/linux -rwxr-xr-x 1 root root 2628 Mar 1 06:19 boot.scr -rwxr-xr-x 1 root root 67938 Mar 1 06:19 imx6dl-ccimx6sbc-id131.dtb -rwxr-xr-x 1 root root 67823 Mar 1 06:19 imx6dl-ccimx6sbc-w.dtb -rwxr-xr-x 1 root root 67960 Mar 1 06:19 imx6dl-ccimx6sbc-wb.dtb -rwxr-xr-x 1 root root 67644 Mar 1 06:19 imx6dl-ccimx6sbc.dtb -rwxr-xr-x 1 root root 71640 Mar 1 06:19 imx6q-ccimx6sbc-id129.dtb -rwxr-xr-x 1 root root 71648 Mar 1 06:19 imx6q-ccimx6sbc-id130.dtb -rwxr-xr-x 1 root root 71503 Mar 1 06:19 imx6q-ccimx6sbc-w.dtb -rwxr-xr-x 1 root root 71836 Mar 1 06:19 imx6q-ccimx6sbc-wb-ldo-bypass.dtb -rwxr-xr-x 1 root root 71640 Mar 1 06:19 imx6q-ccimx6sbc-wb.dtb -rwxr-xr-x 1 root root 71328 Mar 1 06:19 imx6q-ccimx6sbc.dtb -rwxr-xr-x 1 root root 6910352 Mar 1 06:19 zImage-ccimx6sbc.bin
To update the files from user space, remount the linux partition with read/write permissions:
~$ mount -o remount,rw /dev/mmcblk0p1 /mnt/linux
From your development machine, you can now copy the files to the target via ssh. For example:
~$ scp zImage root@<cc6-ip>:/mnt/linux/zImage-ccimx6sbc.bin
When building from Digi Embedded Yocto, all the elements are packaged together in a single file:
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dey-image-qt-xwayland-ccimx6sbc.boot.vfat or similar on the ConnectCore 6 SBC.
To update the entire linux partition from U-Boot console, save the image file to your TFTP server and use the update command in U-Boot:
=> update linux tftp <filename>