Yocto NAND Flash Burning
From Variscite Wiki
Installing Yocto to the SOM's internal storage
Introduction
All SOMs can either boot from an SD card or from their internal storage.
The SOM's internal storage:
The Variscite DART-6UL has either an on-SOM NAND flash or eMMC, and either of them can be used to boot from and to hold the file system.
For NAND flash we use a UBI file system and for eMMC we use ext4.
NAND flash structure
0x000000000000-0x000000200000 : "spl"
0x000000200000-0x000000400000 : "u-boot"
0x000000400000-0x000000600000 : "u-boot_env"
0x000000600000-0x000000e00000 : "kernel"
0x000000e00000-End : "rootfs"
eMMC structure
0-4 MiB : Non-partitioned space, saved for U-Boot.
4-12 MiB : BOOT-VAR6UL - A FAT16 partition containing the Linux image and the device tree blob/s.
12 MiB-End: "rootfs" - An ext4 partition containing the root file system (including the kernel modules).
Yocto Built binaries for NAND flash / eMMC
The resulting images are located at tmp/deploy/images/imx6ul-var-dart.
| Image Name |
How to use |
|---|---|
| fsl-image-gui-imx6ul-var-dart.wic.gz | This image is for SD card boot. It can be flashed as-is on an SD card that can then be used to boot your system, according to the relevant startup-guide of your product (usually requires to press the boot select button, or toggle a DIP switch). For detailed information refer to the Create a bootable SD card section below. |
| fsl-image-gui-imx6ul-var-dart.tar.gz | Tarball with rootfs files. Can be used to create an NFS root file system on the host. See the Yocto Setup TFTP/NFS section for more info. Also used to create our extended SD card. See the Create a bootable SD card section below. |
| fsl-image-gui-imx6ul-var-dart_128kbpeb.ubi | A complete UBI image containing a UBIFS volume, for writing to NAND flash with 128KiB PEB |
| fsl-image-gui-imx6ul-var-dart_256kbpeb.ubi | A complete UBI image containing a UBIFS volume, for writing to NAND flash with 256KiB PEB |
| zImage | Linux kernel image, same binary for SD card/eMMC or NAND flash. |
| SPL-sd | SPL built for SD card boot or eMMC boot. |
| SPL-nand | SPL built for NAND flash. |
| u-boot.img-sd | U-Boot built for SD card boot or eMMC boot. |
| u-boot.img-nand | U-Boot built for NAND flash. |
| File Name | Description |
|---|---|
| imx6ull-var-dart-6ulcustomboard-emmc-sd-card.dtb | Device tree blob for DART-6UL with i.MX6ULL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ull-var-dart-6ulcustomboard-emmc-wifi.dtb | Device tree blob for DART-6UL with i.MX6ULL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ull-var-dart-6ulcustomboard-nand-sd-card.dtb | Device tree blob for DART-6UL with i.MX6ULL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ull-var-dart-6ulcustomboard-nand-wifi.dtb | Device tree blob for DART-6UL with i.MX6ULL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ul-var-dart-6ulcustomboard-emmc-sd-card.dtb | Device tree blob for DART-6UL with i.MX6UL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ul-var-dart-6ulcustomboard-emmc-wifi.dtb | Device tree blob for DART-6UL with i.MX6UL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ul-var-dart-6ulcustomboard-nand-sd-card.dtb | Device tree blob for DART-6UL with i.MX6UL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ul-var-dart-6ulcustomboard-nand-wifi.dtb | Device tree blob for DART-6UL with i.MX6UL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ulz-var-dart-6ulcustomboard-emmc-sd-card.dtb | Device tree blob for DART-6UL with i.MX6ULZ SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ulz-var-dart-6ulcustomboard-emmc-wifi.dtb | Device tree blob for DART-6UL with i.MX6ULZ SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ulz-var-dart-6ulcustomboard-nand-sd-card.dtb | Device tree blob for DART-6UL with i.MX6ULZ SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ulz-var-dart-6ulcustomboard-nand-wifi.dtb | Device tree blob for DART-6UL with i.MX6ULZ SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ull-var-som-concerto-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ull-var-som-concerto-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ull-var-som-concerto-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ull-var-som-concerto-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ul-var-som-concerto-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6UL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ul-var-som-concerto-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6UL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ul-var-som-concerto-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6UL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ul-var-som-concerto-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6UL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ulz-var-som-concerto-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULZ SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ulz-var-som-concerto-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULZ SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ulz-var-som-concerto-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULZ SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ulz-var-som-concerto-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Concerto board with i.MX6ULZ SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ull-var-som-symphony-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ull-var-som-symphony-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ull-var-som-symphony-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ull-var-som-symphony-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ul-var-som-symphony-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6UL SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ul-var-som-symphony-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6UL SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ul-var-som-symphony-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6UL SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ul-var-som-symphony-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6UL SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
| imx6ulz-var-som-symphony-board-emmc-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULZ SOC, eMMC & SD card enabled. (NAND flash & WiFi disabled) |
| imx6ulz-var-som-symphony-board-emmc-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULZ SOC, eMMC & WiFi enabled. (NAND flash & SD card disabled) |
| imx6ulz-var-som-symphony-board-nand-sd-card.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULZ SOC, NAND flash & SD card enabled. (eMMC & WiFi disabled) |
| imx6ulz-var-som-symphony-board-nand-wifi.dtb | Device tree blob for VAR-SOM-6UL on Symphony board with i.MX6ULZ SOC, NAND flash & WiFi enabled. (eMMC & SD card disabled) |
Installing the Yocto binaries
If you followed the Create an extended SD card steps, the Yocto binaries and the flashing scripts will be included in your SD card.
The flashing scripts are easy-to-use example scripts for flashing images into NAND flash / eMMC.
There is also a section below describing how to flash the images manually.
Images locations
Following is the directory structure on your SD card, which elaborates the files' location that the below installation scripts are expecting:
/opt/images/
└── Yocto
├── imx6ull-var-dart-6ulcustomboard-emmc-sd-card.dtb
├── imx6ull-var-dart-6ulcustomboard-emmc-wifi.dtb
├── imx6ull-var-dart-6ulcustomboard-nand-sd-card.dtb
├── imx6ull-var-dart-6ulcustomboard-nand-wifi.dtb
├── imx6ull-var-som-concerto-board-emmc-sd-card.dtb
├── imx6ull-var-som-concerto-board-emmc-wifi.dtb
├── imx6ull-var-som-concerto-board-nand-sd-card.dtb
├── imx6ull-var-som-concerto-board-nand-wifi.dtb
├── imx6ull-var-som-symphony-board-emmc-sd-card.dtb
├── imx6ull-var-som-symphony-board-emmc-wifi.dtb
├── imx6ull-var-som-symphony-board-nand-sd-card.dtb
├── imx6ull-var-som-symphony-board-nand-wifi.dtb
├── imx6ul-var-dart-6ulcustomboard-emmc-sd-card.dtb
├── imx6ul-var-dart-6ulcustomboard-emmc-wifi.dtb
├── imx6ul-var-dart-6ulcustomboard-nand-sd-card.dtb
├── imx6ul-var-dart-6ulcustomboard-nand-wifi.dtb
├── imx6ul-var-som-concerto-board-emmc-sd-card.dtb
├── imx6ul-var-som-concerto-board-emmc-wifi.dtb
├── imx6ul-var-som-concerto-board-nand-sd-card.dtb
├── imx6ul-var-som-symphony-board-emmc-sd-card.dtb
├── imx6ul-var-som-symphony-board-emmc-wifi.dtb
├── imx6ul-var-som-symphony-board-nand-sd-card.dtb
├── imx6ul-var-som-symphony-board-nand-wifi.dtb
├── imx6ul-var-som-concerto-board-nand-wifi.dtb
├── imx6ulz-var-dart-6ulcustomboard-emmc-sd-card.dtb
├── imx6ulz-var-dart-6ulcustomboard-emmc-wifi.dtb
├── imx6ulz-var-dart-6ulcustomboard-nand-sd-card.dtb
├── imx6ulz-var-dart-6ulcustomboard-nand-wifi.dtb
├── imx6ulz-var-som-concerto-board-emmc-sd-card.dtb
├── imx6ulz-var-som-concerto-board-emmc-wifi.dtb
├── imx6ulz-var-som-concerto-board-nand-sd-card.dtb
├── imx6ulz-var-som-concerto-board-nand-wifi.dtb
├── imx6ulz-var-som-symphony-board-emmc-sd-card.dtb
├── imx6ulz-var-som-symphony-board-emmc-wifi.dtb
├── imx6ulz-var-som-symphony-board-nand-sd-card.dtb
├── imx6ulz-var-som-symphony-board-nand-wifi.dtb
├── rootfs_128kbpeb.ubi
├── rootfs_256kbpeb.ubi
├── rootfs.tar.gz
├── SPL-nand
├── SPL-sd
├── u-boot.img-nand
├── u-boot.img-sd
└── zImage
Prepare the images for NAND flash / eMMC flashing
Plug the bootable SD card into your host machine and mount the rootfs partition - here we assume it is mounted on /media/rootfs.
Copy all the mentioned yocto-built binaries to the SD card:
- Note: If you followed the Create an extended SD card steps, the flashing scripts and all relevant binaries are already included in your SD card, and the below commands are redundant!
Setup:
$ export YOCTO_IMGS_PATH=~/var-fsl-yocto/build_x11/tmp/deploy/images/imx6ul-var-dart
$ export P2_MOUNT_DIR=/media/rootfs/
$ sudo mkdir -p ${P2_MOUNT_DIR}/opt/images/Yocto/
Linux:
$ sudo cp ${YOCTO_IMGS_PATH}/zImage ${P2_MOUNT_DIR}/opt/images/Yocto/
Device Tree:
$ for f in ${YOCTO_IMGS_PATH}/*.dtb; do if [[ -L $f ]] && [[ $f != *imx6ul-var-dart.dtb ]]; then sudo cp $f ${P2_MOUNT_DIR}/opt/images/Yocto/; fi done
$ sudo rename 's/zImage-imx/imx/' ${P2_MOUNT_DIR}/opt/images/Yocto/*.dtb
NAND images:
SPL:
$ sudo cp ${YOCTO_IMGS_PATH}/SPL-nand ${P2_MOUNT_DIR}/opt/images/Yocto/
U-Boot:
$ sudo cp ${YOCTO_IMGS_PATH}/u-boot.img-nand ${P2_MOUNT_DIR}/opt/images/Yocto/
File System:
$ sudo cp ${YOCTO_IMGS_PATH}/fsl-image-gui-imx6ul-var-dart.ubi ${P2_MOUNT_DIR}/opt/images/Yocto/rootfs.ubi
eMMC images:
SPL:
$ sudo cp ${YOCTO_IMGS_PATH}/SPL-sd ${P2_MOUNT_DIR}/opt/images/Yocto/
U-Boot:
$ sudo cp ${YOCTO_IMGS_PATH}/u-boot.img-sd ${P2_MOUNT_DIR}/opt/images/Yocto/
File System:
$ sudo cp ${YOCTO_IMGS_PATH}/fsl-image-gui-imx6ul-var-dart.tar.gz ${P2_MOUNT_DIR}/opt/images/Yocto/rootfs.tar.gz
Flashing scripts
The flashing scripts are located on the SD card at /usr/bin/:
install_yocto.sh - Flash Yocto into NAND flash or eMMC (Run and follow usage instructions)
Manual step-by-step flashing to NAND flash
Use the prepared SD card to boot the board and run the following:
$ cd /opt/images/{{#var:PLATFORM_OS}}
Flash SPL & U-Boot:
$ flash_erase /dev/mtd0 0 0 $ kobs-ng init -x SPL-nand --search_exponent=1 -v $ flash_erase /dev/mtd1 0 0 $ nandwrite -p /dev/mtd1 u-boot.img-nand $ flash_erase /dev/mtd2 0 0
Flash the Linux Kernel image & Device Tree:
You need to use the right .dtb file for you hardware setup. See the table above for a complete description.
$ flash_erase /dev/mtd3 0 0 $ nandwrite -p /dev/mtd3 zImage $ nandwrite -p /dev/mtd3 -s 0x7e0000 <DEVICE_TREE_FILE>
Flash the (UBI) File System to NAND flash:
$ ubiformat /dev/mtd4 -f rootfs.ubi
Manual step-by-step flashing to eMMC
Flashing the eMMC requires several steps including partitioning, file system formatting and image extraction.
We recommend to use our provided scripts to perform this task.
Use the prepared SD card to boot the board and run the following:
$ export node=/dev/mmcblk1 $ cd /opt/images/Yocto
Make sure the eMMC is not mounted:
$ umount ${node}p*
Delete current data on eMMC:
$ dd if=/dev/zero of=${node}p1 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p2 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p3 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p4 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p5 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p6 bs=1024 count=1024
$ dd if=/dev/zero of=${node}p7 bs=1024 count=1024
$ sync
$ (echo d; echo 1; echo d; echo 2; echo d; echo 3; echo d; echo w) | fdisk ${node}
$ sync
$ dd if=/dev/zero of=${node} bs=1M count=4
$ sync
Create a partition table:
$(echo n; echo p; echo 1; echo 8192; echo 24575; echo t; echo c; \
echo n; echo p; echo 2; echo 24576; echo; \
echo p; echo w) | fdisk -u ${node}
$ sync
Format the partitions:
$ mkfs.vfat ${node}p1 -n BOOT-VAR6UL
$ mkfs.ext4 ${node}p2 -L rootfs
Flash SPL and U-Boot to eMMC:
$ dd if=SPL-sd of=${node} bs=1K seek=1; sync
$ dd if=u-boot.img-sd of=${node} bs=1K seek=69; sync
Copy the Linux kernel image and the device tree blobs to the BOOT partition:
$ mkdir /run/media/mmcblk1p1
$ mount -t vfat ${node}p1 /run/media/mmcblk1p1/
$ cp *emmc*.dtb /run/media/mmcblk1p1/
$ cp zImage /run/media/mmcblk1p1/
$ sync
$ umount /run/media/mmcblk1p1
Extract the rootfs archive:
$ mkdir /run/media/mmcblk1p2
$ mount ${node}p2 /run/media/mmcblk1p2
$ tar xvpf rootfs.tar.gz -C /run/media/mmcblk1p2
$ sync
$ umount /run/media/mmcblk1p2
Summary
We described the results of a Yocto build, how to copy it to a bootable SD card and how to flash it to NAND and eMMC.
With our extended SD card and our recovery SD card we provide an installation script located at /usr/bin/install_yocto.sh. It is much safer to use it instead of flashing the system manually.