DESK-MX8M-L/Development/How to create a bootable microSD card

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History
ID#	Issue Date	Notes
16139	17/02/2022	First DESK-MX8M-L release
17546	24/02/2023	DESK-MX8M-L-2.0.0 release
17546	25/07/2023	DESK-MX8M-L-4.0.0 release

How to create a bootable SD card[edit | edit source]

The procedure described here was tested with a virtual machine such as the MVM. The USB controller of the MVM should be enabled by default. If you are using Linux-based distribution and are having trouble detecting a USB device in virtual machine, please make sure your user belongs to the vboxusers group.

This article shows how to create a bootable microSD for the [[DESK-MX8M-L/General/Release_Notes_(DESK-MX8M-L)|DESK-MX8M-L Release Notes] kit by using a simple bash script.
Note: Starting from DESK-MX8M-L-2.0.0 release the support for the SPL has been introduced in U-Boot. Previous versions of this script will no longer produce a fully functional and bootable microSD card.

The procedure has been tested on a MVM released with DESK-MX8M-L 4.0.0 release with

a 32 GB microSD card [1]
a USB SD card reader
the binary files delivered along with the DESK-MX8M-L 4.0.0

The resulting card is partitioned as depicted here.

The script - named desk-mx8m-l-4.0.0_mksd.sh - can be realized with the following code:

#!/bin/bash

if [[ -z $1 || -z $2 || -z $3 || -z $4 ]]
then
	echo "$0 Usage:"
	echo "	$0 <device> <flash.bin> <binaries directory> <rootfs tar.bz2>"
	echo "	Example: $0 /dev/sdc flash.bin binaries/ rootfs.tar.bz2"
	exit
fi

if [ "$(whoami)" != "root" ]
then
	echo "you must be root to run this script!"
	exit
fi

if ! [[ -b $1 ]]
then
	echo "$1 is not a valid block device!"
	exit
fi

if ! [[ -e $2 ]]
then
	echo "Incorrect flash.bin location!"
	exit
fi

if ! [[ -d $3 ]]
then
	echo "Incorrect Binaries location!"
	exit
fi

if ! [[ -f $4 ]]
then
	echo "Incorrect rootfs location!"
	exit
fi

DRIVE=$1
if [[ "$DRIVE" == *"mmcblk"* ]]
then
	echo "You're using a mmc device, I need to fix partition names"
	PART="p"
else
	PART=""
fi
BOOT=$2
BINARIES=$3
RFS=$4

echo "All data on "$DRIVE" now will be destroyed! Continue? [y/n]"
read ans
if ! [ $ans == 'y' ]
then
	exit
fi

echo "[Partitioning $1...]"

dd if=/dev/zero of=$DRIVE bs=1024 count=1024

SIZE=`fdisk -l $DRIVE | grep Disk | awk '{print $5}'`

echo DISK SIZE - $SIZE bytes

CYLINDERS=`echo $SIZE/255/63/512 | bc`

# check if we're running an old (e.g. 2.20.x) or new (e.g. 2.24.x) sfdisk
sfdisk --help | grep -- -H

if [ "$?" -eq "0" ]
then
	{
		echo 40,1380,0x0c,*
		echo 1420,,83,-
	} | sfdisk -D -H 255 -S 63 -C $CYLINDERS $DRIVE
else
{
    echo 16M,8176M,0x0c,*
    echo 8192M,,83,-
} | sfdisk $DRIVE
fi

partprobe


echo "[Making filesystems...]"
mkfs.vfat -F 32 -n BOOT "$DRIVE$PART"1 #> /dev/null
mkfs.ext3 -F -L ROOTFS "$DRIVE$PART"2 #> /dev/null

echo "[Copying files...]"

binaries_dir=${BINARIES%/}
mount "$DRIVE$PART"1 /mnt
cp -av --no-preserve=ownership $binaries_dir/* /mnt/
umount "$DRIVE$PART"1

echo "[Extracting rfs (this may take a while...)]"
mount "$DRIVE$PART"2 /mnt
tar jxf $RFS -C /mnt > /dev/null
chmod 755 /mnt
umount "$DRIVE$PART"2

echo "[Programming flash.bin]"
dd if=$BOOT of=$DRIVE bs=1k seek=32 conv=fsync

echo "[Done]"

if you are making a uSD for MITO 8M Mini SOM, then the last line must be modified with dd if=$BOOT of=$DRIVE bs=1k seek=33.

Here is an example that shows how to use this script. We use here files delivered with DESK-MX8M-L 4.0.0 release. Before invoking the script, the following files has to be renamed in order to make them compatible with the default U-Boot environment variables:

bootscript: boot.scr
Linux kernel: Image
Device tree blob: imx8mp-mito8mplus-cb1008.dtb or imx8mm-mito8mmini-cb100a.dtb

Let's start with creating boot.scr. On MVM there is /home/dvdk/desk-mx-l/desk-mx8m-l-4.0.0_bootscript.txt file that we can use to create needed file.

Here below there is an example on how to create a boot.scr file from the desk-mx8m-l-4.0.0_bootscript.txt for booting from SD card:

echo 'bootscript generated with command "mkimage -A ARM -T script -C none -n DESK-MX8M -d bootscript.txt boot.scr"'

setenv desk_release 'desk-mx8m-l-4.0.0'

if test 0x${cb_configid#} = 0x00001001;
then
	setenv fdtfile imx8mp-mito8mplus-cb1001.dtb
elif test 0x${cb_configid#} = 0x00001004;
then
	setenv fdtfile imx8mp-mito8mplus-cb1004.dtb
elif test 0x${cb_configid#} = 0x00001005;
then
	setenv fdtfile imx8mp-mito8mplus-cb1005.dtb
	# CM7 boot
	setenv cm7_loadaddr 0x48000000
	setenv cm7_tcm_start 0x7e0000
	setenv cm7_boot 'fatload mmc ${sd_dev}:1 ${cm7_loadaddr} stress_m7.bin;cp.b ${cm7_loadaddr} ${cm7_tcm_start} 20000; bootaux ${cm7_tcm_start}'
elif test 0x${cb_configid#} = 0x00001008;
then
	setenv fdtfile imx8mp-mito8mplus-cb1008.dtb
elif test 0x${cb_configid#} = 0x0000100a;
then
	setenv fdtfile imx8mm-mito8mmini-cb100a.dtb
else
	echo Invalid CB ConfigID! Autoreset ...
	sleep 30
	reset
fi

setenv bootfile Image
setenv mmc_loadk 'fatload mmc ${sd_dev}:1 ${loadaddr} ${bootfile}'
setenv mmc_loadfdt 'fatload mmc ${sd_dev}:1 ${fdt_addr} ${fdtfile}'
setenv mmcboot 'run mmc_loadk; run mmc_loadfdt; run bootk'
setenv bootargs 'console=ttymxc1,115200 earlycon=ec_imx6q,0x30890000,115200 root=/dev/mmcblk1p2'
setenv bootk 'booti ${loadaddr} - ${fdt_addr}'

echo Booting DESK-MX8M via mmcboot with ${fdtfile} as device tree

run mmcboot

echo mmcboot FAILURE

and compile it using:

dvdk@vagrant:~$ mkimage -A ARM -T script -C none -n DESK-MX8M -d ~/desk-mx-l/desk-mx8m-l-4.0.0_bootscript.txt ~/desk-mx-l/boot.scr
Image Name:   DESK-MX8M
Created:      Tue Jul 25 12:24:35 2023
Image Type:   ARM Linux Script (uncompressed)
Data Size:    1371 Bytes = 1.34 KiB = 0.00 MiB
Load Address: 00000000
Entry Point:  00000000
Contents:
   Image 0: 1363 Bytes = 1.33 KiB = 0.00 MiB
dvdk@vagrant:~$

In the case of you don't have some file on MVM, please download it from mirro.dave.eu.

We will copy them into ~/desk-mx-l/desk directory. Needed binary files can be found on MVM in the following location:

dvdk@vagrant:~$ mkdir -p ~/desk-mx-l/desk
dvdk@vagrant:~$ cd ~/desk-mx-l/desk
dvdk@vagrant:~/desk-mx-l/desk$ ls /tftpboot/desk-mx8m-l/ -l
total 34872
-rw-r--r-- 1 dvdk root 31351296 Jul 24 08:50 desk-mx8m-l-4.0.0_Image
-rw-r--r-- 1 dvdk root  1406688 Jul 24 08:48 desk-mx8m-l-4.0.0_imx8mm_flash.bin
-rw-r--r-- 1 dvdk root    43034 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mm-mito8mmini-cb100a.dtb
-rw-r--r-- 1 dvdk root    43022 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mm-mito8mmini.dtb
-rw-r--r-- 1 dvdk root  1433040 Jul 24 08:48 desk-mx8m-l-4.0.0_imx8mp_flash.bin
-rw-r--r-- 1 dvdk root    60443 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mp-mito8mplus-cb1001.dtb
-rw-r--r-- 1 dvdk root    62520 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mp-mito8mplus-cb1004.dtb
-rw-r--r-- 1 dvdk root    61258 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mp-mito8mplus-cb1005.dtb
-rw-r--r-- 1 dvdk root    61299 Jul 24 08:50 desk-mx8m-l-4.0.0_imx8mp-mito8mplus-cb1008.dtb
lrwxrwxrwx 1 root root       49 Jul 24 09:42 Image -> /tftpboot/desk-mx8m-l/desk-mx8m-l-4.0.0_Image
lrwxrwxrwx 1 root root       60 Jul 24 09:42 imx8mm_flash.bin -> /tftpboot/desk-mx8m-l/desk-mx8m-l-4.0.0_imx8mm_flash.bin
lrwxrwxrwx 1 root root       72 Jul 24 09:42 imx8mm-mito8mmini-cb100a.dtb -> /tftpboot/desk-mx8m-l/desk-mx8m-l-4.0.0_imx8mm-mito8mmini-cb100a.dtb
lrwxrwxrwx 1 root root       60 Jul 24 09:42 imx8mp_flash.bin -> /tftpboot/desk-mx8m-l/desk-mx8m-l-4.0.0_imx8mp_flash.bin
lrwxrwxrwx 1 root root       72 Jul 24 09:42 imx8mp-mito8mplus-cb1008.dtb -> /tftpboot/desk-mx8m-l/desk-mx8m-l-4.0.0_imx8mp-mito8mplus-cb1008.dtb
-rw-r--r-- 1 dvdk root  1152054 Jul 24 08:48 splash_image.bmp
dvdk@vagrant:~/desk-mx-l/desk$ mkdir binaries
dvdk@vagrant:~/desk-mx-l/desk$ cp /tftpboot/desk-mx8m-l/Image binaries/
dvdk@vagrant:~/desk-mx-l/desk$ cp /tftpboot/desk-mx8m-l/imx8mp-mito8mplus-cb1008.dtb binaries/
dvdk@vagrant:~/desk-mx-l/desk$ cp ~/desk-mx-l/boot.scr binaries/
dvdk@vagrant:~/desk-mx-l/desk$ cp /tftpboot/desk-mx8m-l/imx8mp_flash.bin flash.bin
dvdk@vagrant:~/desk-mx-l/desk$

You can now run the script, by passing the following parameters:

Device file of the microSD card (/dev/sdb in the example)
Boot image
Path of the directory containing the bootscript file, the Linux kernel image, and the device tree blob files
Archive of the target's root file system (compressed as .tar.bz2 file).

dvdk@vagrant:~/desk-mx-l/desk$ cd ~/desk-mx-l/
dvdk@vagrant:~/desk-mx-l$ sudo umount /dev/sdb*
umount: /dev/sdb: not mounted.
umount: /dev/sdb1: not mounted.
dvdk@vagrant:~/desk-mx-l$ sudo ./desk-mx8m-l-4.0.0_mksd.sh /dev/sdb desk/flash.bin desk/binaries/ rfs/desk-mx8m-l-4.0.0_desk-image-qt6-desk-mx8mp.tar.bz2 
All data on /dev/sdb now will be destroyed! Continue? [y/n]
y
[Partitioning /dev/sdb...]
1024+0 records in
1024+0 records out
1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.285905 s, 3.7 MB/s
DISK SIZE - 31914983424 bytes
Checking that no-one is using this disk right now ... OK

Disk /dev/sdb: 29.74 GiB, 31914983424 bytes, 62333952 sectors
Disk model: Transcend       
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

>>> Created a new DOS disklabel with disk identifier 0x688f6e07.
/dev/sdb1: Created a new partition 1 of type 'W95 FAT32 (LBA)' and of size 8 GiB.
/dev/sdb2: Created a new partition 2 of type 'Linux' and of size 21.7 GiB.
/dev/sdb3: Done.

New situation:
Disklabel type: dos
Disk identifier: 0x688f6e07

Device     Boot    Start      End  Sectors  Size Id Type
/dev/sdb1  *       32768 16777215 16744448    8G  c W95 FAT32 (LBA)
/dev/sdb2       16777216 62333951 45556736 21.7G 83 Linux

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
[Making filesystems...]
mkfs.fat 4.1 (2017-01-24)
mke2fs 1.45.5 (07-Jan-2020)
Creating filesystem with 5694592 4k blocks and 1425408 inodes
Filesystem UUID: 393fccfd-00af-487c-ae97-a255d18ab558
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000

Allocating group tables: done 
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   

[Copying files...]
'desk/binaries/boot.scr' -> '/mnt/boot.scr'
'desk/binaries/desk-mx8m-l-4.0.0-rc2_bootscript.txt' -> '/mnt/desk-mx8m-l-4.0.0-rc2_bootscript.txt'
'desk/binaries/Image' -> '/mnt/Image'
'desk/binaries/imx8mp-mito8mplus-cb1008.dtb' -> '/mnt/imx8mp-mito8mplus-cb1008.dtb'
[Extracting rfs (this may take a while...)]
[Programming flash.bin]
1399+1 records in
1399+1 records out
1433040 bytes (1.4 MB, 1.4 MiB) copied, 0.30112 s, 4.8 MB/s
[Done]
dvdk@vagrant:~/desk-mx-l$

[1] In case you have a different size, you'll need to change the sfdisk parameters accordingly.

HOME	SOMs	SBCs	ToloMEO Embedded Assistant	GET A QUOTE	ONLINE HELPDESK
	Roadmap		IoT Services			ML/AI services	Embedded Design Services

DESK-MX8M-L/Development/How to create a bootable microSD card

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How to create a bootable SD card[edit | edit source]

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