DART-6UL NAND Flash Burning

DART-6UL - NAND Flash Burning

Introduction

The Variscite DART-6UL use the on-SOM NAND flash or eMMC to boot.
The file system can reside either on the NAND flash or the eMMC.
When file system resides on NAND, UBI file system will be used.
When file system resides on eMMC, ext4 file system will be used.

NOTE:
This WIKI is only valid for DART-6UL.

NAND Structure

When system boots, kernel logs will present 5 relevant partitions defined.

0x000000000000-0x000000200000 : "spl"
0x000000200000-0x000000400000 : "uboot"
0x000000400000-0x000000600000 : "uboot-env"
0x000000600000-0x000000e00000 : "kernel"
0x000000e00000-0x000040000000 : "rootfs"

Yocto Built binaries for NAND-Flash

The resulted images are located in tmp/deploy/images/imx6ul-var-dart/.
Looking at tmp/deploy/images/imx6ul-var-dart/ you will find 6 main files that are linked to the actual file

Image Name	How to use
fsl-image-gui-imx6ul-var-dart.sdcard	This image is for SD-Card boot. Default u-boot is built for SDCARD. Booting from SD-Card is explained in details below. See section 8.1 below for the sdcard structure.
fsl-image-gui-imx6ul-var-dart.tar.bz2	Used to create an NFS root file system on the host. See apendix for setting an NFS server
fsl-image-gui-imx6ul-var-dart.ubi	Use the sdcard created above. Copy the file into it and use the following commands to flash them into nand. Coping files (mount the sd-card created above first):
zImage	Linux kernel image
u-boot-nand-2015.04-r0.imx	u-boot built for nand
u-boot-sd-2015.04-r0.imx	u-boot built for sdcard/eMMC
Device Tree Name	Boot Device
zImage-imx6ul-var-dart-emmc_wifi.dtb	Boot from internal eMMC with WI-FI enabled. (SDCARD & NAND disabled)
zImage-imx6ul-var-dart-nand_wifi.dtb	Boot from internal NAND with WI-FI enabled. (SDCARD & eMMC disabled)
zImage-imx6ul-var-dart-sd_emmc.dtb	SDCARD and eMMC enabled (WIFI & NAND disabled). You can boot from eMMC or SDCARD
zImage-imx6ul-var-dart-sd_nand.dtb	SDCARD and NAND enabled (WIFI & eMMC disabled). You can boot from NAND or SDCARD

NAND Flashing scripts

If you followed Create an extended SD-Card the NAND flashing scripts will be included in your SD-Card.
The NAND flashing scripts are easy-to-use example scripts for burning images into NAND Flash

NAND-Flash images locations

The below directory stucture on your SD-Card, elaborates the files' location which the below burning scripts are expecting

/media/rootfs/opt/images/
└── Yocto
    ├── rootfs.sdcard
    ├── rootfs.tar.bz2
    ├── rootfs.ubi.img
    ├── SPL-nand
    ├── SPL-sd
    ├── u-boot-nand-2015.04-r0.img
    ├── u-boot-sd-2015.04-r0.img
    ├── zImage
    ├── zImage-imx6ul-var-dart-emmc_wifi.dtb
    ├── zImage-imx6ul-var-dart-nand_wifi.dtb
    ├── zImage-imx6ul-var-dart-sd_emmc.dtb
    └── zImage-imx6ul-var-dart-sd_nand.dtb

Script files located on /media/rootfs/sbin/
yocto-nand.sh
nand-recovery.sh
yocto-emmc.sh

Prepare images for NAND-Flash / eMMC burning

Plug the bootable SDCARD into your host machine. Then your host machine should mount the rootfs partition on /media/rootfs.
Copy all yocto-built binaries into SD-Card:

• Note: If you followed Create an extended SD-Card the NAND flashing scripts and all relevant binaries are already included in your SD-Card! and below commands are redundant
  

$ export YOCTO_ROOT=~/var-dart-6ul-yocto-fido

Linux:
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/zImage  /media/rootfs/opt/images/Yocto
U-boot:
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/SPL-nand /tmp/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/SPL-sd   /tmp/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/u-boot-nand-2015.04-r0.img /tmp/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/u-boot-sd-2015.04-r0.img   /tmp/rootfs/opt/images/Yocto/
File System:
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/fsl-image-gui-imx6ul-var-dart.tar.bz2 /media/rootfs/opt/images/Yocto/rootfs.tar.bz2
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/fsl-image-gui-imx6ul-var-dart.ubi /media/rootfs/opt/images/Yocto/rootfs.ubi.img
Device Tree:
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/zImage-imx6ul-var-dart-emmc_wifi.dtb /media/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/zImage-imx6ul-var-dart-nand_wifi.dtb /media/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/zImage-imx6ul-var-dart-sd_emmc.dtb /media/rootfs/opt/images/Yocto/
$ sudo cp ${YOCTO_ROOT}/build_x11/tmp/deploy/images/imx6ul-var-dart/zImage-imx6ul-var-dart-sd_nand.dtb /media/rootfs/opt/images/Yocto/

NAND-Flash Flashing scripts

The flashing scripts are located at /media/rootfs/sbin/

$ yocto-emmc.sh - flash Yocto into eMMC
$ yocto-nand.sh - flash Yocto into nand

Manual step-by-step flashing to NAND

Flash U-BOOT

Flashing U-BOOT reguire to flash 2 parts: SPL and u-boot.img. Assume you copy SPL-nand and u-boot-nand-2014.04-r0.img to the right directory as showed above.

$ cd /opt/images/Yocto
$ 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-nand-2015.04-r0.img

Flash Linux Kernel

Flashing Linux kernel reguire to flash 2 parts: uImage and device tree. Assume you copy uImage and device tree to the right directory as showed above. You also need to pick and coose the right DTB file. See table above for a complete description.

$ cd /opt/images/Yocto
$ flash_erase /dev/mtd3 0 0
$ nandwrite -p /dev/mtd3 zImage
$ nandwrite -p /dev/mtd3 -s 0x7e0000 zImage-imx6ul-var-dart-nand_wifi.dtb  (Example, select the right one!)

Flash UBIFS

The parameters for the UBIFS UBI_SUB_PAGE_SIZE=2048 and UBI_VID_HDR_OFFSET=2048.

$ cd /opt/images/Yocto
$ flash_erase /dev/mtd4 0 0
$ ubiformat /dev/mtd4 -f rootfs.ubi.img -s 2048 -O 2048

Flash File System to eMMC

We highly recommend to use our above mentioned provided scripts to perform this task as an example

Make sure the eMMC is not mounted.

$ cd /opt/images/Yocto
$ umount /dev/mmcblk1p*
$ node=/dev/mmcblk1 

Delete all partition from the eMMC.

$fdisk /dev/mmcblk1 1>/dev/null <<EOF 
d
1
d
2
d
3
d
w
EOF

$ sync 

Delete MBR

$ dd if=/dev/zero of=${node} bs=512 count=1000
$ sync

Call fdisk to create partition table

$ fdisk /dev/mmcblk1 <<EOF 
n
p
1
8192
24575
t
c
n
p
2
24576

p
w
EOF

Format Linux

$ mkfs.vfat /dev/mmcblk1p1 -nBOT_DART6UL
$ mkfs.ext4 /dev/mmcblk1p2 -Lrootfs

Flash the file system and copy the relevant files to tjhe boot partition.

$ mount | grep mmcblk1   
u-boot:
$ sudo dd if=SPL-sd of=/dev/mmcblk1 bs=1K seek=1; sync
$ sudo dd if=u-boot-sd-2015.04-r0.img of=/dev/mmcblk1 bs=1K seek=69; sync
Mount:
$ mkdir -p /tmp/media/mmcblk1p1
$ mkdir -p /tmp/media/mmcblk1p2
$ mount -t vfat /dev/mmcblk1p1  /tmp/media/mmcblk1p1
$ mount /dev/mmcblk1p2  /tmp/media/mmcblk1p2
Copy files to Yocto BOOT partition:
$ cp zImage-imx6ul-var-dart-emmc_wifi.dtb	/tmp/media/mmcblk1p1/imx6ul-var-dart-emmc_wifi.dtb
$ cp zImage-imx6ul-var-dart-nand_wifi.dtb	/tmp/media/mmcblk1p1/imx6ul-var-dart-nand_wifi.dtb
$ cp zImage-imx6ul-var-dart-sd_emmc.dtb	/tmp/media/mmcblk1p1/imx6ul-var-dart-sd_emmc.dtb
$ cp zImage-imx6ul-var-dart-sd_nand.dtb	/tmp/media/mmcblk1p1/imx6ul-var-dart-sd_nand.dtb
$ cp zImage       				/tmp/media/mmcblk1p1/zImage
flashing Yocto Root file System:
$ rm -rf /tmp/media/mmcblk1p2/*
$ tar xvf rootfs.tar.bz2 -C /tmp/media/mmcblk1p2/

Summary

We described the results of Yocto build, how to copy it to SDCARD and than flash it to NAND or eMMC. With the NAND recovery utility we provide a set of scripts located on /sbin and listed below. It is much easier to use them instead of the manual operation.
/media/rootfs/sbin/:
yocto-nand.sh nand-recovery.sh yocto-emmc.sh. Some of the scripts are used by the others.
Please use:

• yocto-nand.sh To flash Yocto into NAND
• yocto-emmc.sh To flash Yocto into eMMC