DESK-MX8M-L/Development/Building Boot Image

History
Issue Date	Notes
2022/02/18	First DESK-MX8M-L release
2023/02/24	DESK-MX8M-L-2.0.0 release
2023/08/22	DESK-MX8M-L-4.0.0 release
2024/08/06	DESK-MX8M-L-4.2.0 release

Building Boot Image

The following procedure may be used just during the development stage (as an example, for modifying and testing just some part of the overall binary like u-boot). The Yocto build should be used for creating the deployment or production binary artifacts.

Quick reference

Repository Information
URL	git@git.dave.eu:desk-mx-l/desk-mx8-mkimage.git
stable branch	desk-mx8m-l-4.x.x
stable tag	desk-mx8m-l-4.2.0

i.MX8 Boot Image

The System Controller Unit (SCU) represents the evolution of centralized control for system-level resources on i.MX8. The heart of the system controller is a Cortex-M4 that executes System Controller Firmware. The SCF is an essential part of the i.MX8 architecture. Please find more information about SCF here.

TF-A binary bl31.bin, scfw_tcm.bin and u-boot.bin are combined together to generate a binary file called flash.bin; the imx-mkimage tool is used to generate flash.bin which will be flashed into the bootable storage device.

In the following paragraphs we will explain how to get or build those binaries to be combined in a single binary to be flashed in the bootable storage device.

Prepare environment

It is assumed that the development environment has been set up properly as described here.

• start the Linux development VM and login into the system
• open a terminal window and cd into desk-mx8-mkimage directory

dvdk@vagrant:~$ cd desk-mx-l/desk-mx8-mkimage
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$

• in case of needs you can update your local repository with the following git command

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ git checkout desk-mx8m-l-4.2.0
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ git pull

• configure the build environment

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ source ~/desk-mx-l/desk-mx8m-l-4.0.0_env.sh 

Build U-Boot

First step is to build U-Boot binaries: the same instructions can be found in the dedicated wiki page

dvdk@vagrant:~$ cd ~/desk-mx-l/desk-mx8-mkimage/u-boot-imx/
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$

• select the proper defconfig and start the make compilation

For ORCA SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ make imx8mp_mito8mplus_defconfig
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ make -j$(nproc)

For MITO 8M Mini SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ make imx8mm_mito8mmini_defconfig
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ make -j$(nproc)

This steps produce the u-boot-spl.bin and u-boot.bin files used at the last step.

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ ls -la spl/u-boot-spl.bin
-rwxrwxr-x 1 dvdk dvdk 94328 Feb 17 14:56 spl/u-boot-spl.bin
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ ls -la u-boot.bin
-rw-rw-r-- 1 dvdk dvdk 861312 Feb 17 14:55 u-boot.bin
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/u-boot-imx$ 

Build ATF

This process builds the ARM Trusted Firmware: please find more information here

dvdk@vagrant:~$ cd ~/desk-mx-l/desk-mx8-mkimage/imx-atf/
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/imx-atf$

• for building the ATF, the following var has to be unset

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/imx-atf$ unset LDFLAGS

Then, build the TF-A binary for the selected platform.

For ORCA SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/imx-atf$ make PLAT=imx8mp bl31

For MITO 8M Mini SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage/imx-atf$ make PLAT=imx8mm bl31

Get i.MX firmware

This will download the binary archive, accept EULA automatically (you must agree with that) and extract the archive itself

dvdk@vagrant:~$ cd ~/desk-mx-l/desk-mx8-mkimage/
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ ./fetch_firmware.sh 
--2023-07-24 15:25:21--  https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.18.bin
Resolving www.nxp.com (www.nxp.com)... 104.87.170.182
Connecting to www.nxp.com (www.nxp.com)|104.87.170.182|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1513050 (1.4M) [application/octet-stream]
Saving to: ‘firmware-imx-8.18.bin’

firmware-imx-8.18.bin                                       100%[=========================================================================================================================================>]   1.44M  --.-KB/s    in 0.05s   

2023-07-24 15:25:21 (31.1 MB/s) - ‘firmware-imx-8.18.bin’ saved [1513050/1513050]

Welcome to NXP firmware-imx-8.18.bin

WARNING: EULA has been auto-accepted; this implies that you agree with it.
Unpacking file ................................................................................ done
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$

Generate Boot image

After building all pieces of software, create the flash.bin boot Image running:

./${BOARD}_generate_flash.bin

where BOARD is: imx8mp-mito8mplus or imx8mm-mito8mmini

For ORCA SOM:

dvdk@vagrant:~$ cd ~/desk-mx-l/desk-mx8-mkimage/
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ ./imx8mp-mito8mplus_generate_flash.bin 
Compiling mkimage_imx8
PLAT=imx8mp HDMI=no
Compiling mkimage_imx8
gcc  -O2 -pipe -g -feliminate-unused-debug-types  mkimage_imx8.c -o mkimage_imx8 -lz
23582+0 records in
23582+0 records out
94328 bytes (94 kB, 92 KiB) copied, 0.0379032 s, 2.5 MB/s
./../scripts/dtb_check.sh imx8mp-evk.dtb evk.dtb
Use u-boot DTB: imx8mp-evk.dtb
./../scripts/pad_image.sh tee.bin
...
...
...
...
========= OFFSET dump =========
Loader IMAGE:
 header_image_off 	0x0
 dcd_off 		0x0
 image_off 		0x40
 csf_off 		0x2b800
 spl hab block: 	0x91ffc0 0x0 0x2b800

Second Loader IMAGE:
 sld_header_off 	0x58000
 sld_csf_off 		0x59020
 sld hab block: 	0x401fcdc0 0x58000 0x1020

******************************
******************************

flash.bin generated successfully
write it on a SD card with
dd if=flash.bin of=/dev/sdX bs=1k seek=32 conv=fsync

******************************
******************************
dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ 

For MITO M8M Mini SOM:

./imx8mm-mito8mmini_generate_flash.bin 

Binary files can be copied to the tftp root directory /tftpboot/desk-mx-l/ with the following command:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ cp flash.bin /tftpboot/desk-mx8m-l/desk-mx8m-l-4.2.0_imx8mp_flash.bin

For ORCA SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ cp flash.bin /tftpboot/desk-mx8m-l/desk-mx8m-l-4.2.0_imx8mp_flash.bin

For MITO 8M Mini SOM:

dvdk@vagrant:~/desk-mx-l/desk-mx8-mkimage$ cp flash.bin /tftpboot/desk-mx8m-l/desk-mx8m-l-4.2.0_imx8mm_flash.bin

Please refer to this page for more information on how to update the bootloader on your board.