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U-Boot, Myon II

Since Trizeps VIII Mini and Myon II are software compatible, the same bootloader may be used for both modules.

U-Boot based on NXP 4.14.98_2.0.0_ga ssh://
imx_mkimage based on NXP imx_4.14.98_2.0.0_ga ssh://

Previous Versions:

U-Boot imx_mkimage Notes
kuk_imx_v2020.04 kuk_imx_4.14.98_2.0.0_ga Use for Android 11. (Development Status)
kuk_imx_v2019.04_5.4.3_2.0.0 kuk_imx_4.14.98_2.0.0_ga Use for all current OS, except Android 11
kuk_imx_v2018.03_4.14.98_2.0.0_ga kuk_imx_4.14.98_2.0.0_ga Not compatible with Linux 5.4 and later

U-Boot Binaries

Myon II

Date Changelog Download
06.04.2021 - mn2_uboot_20210406.bin

How to Make U-Boot for Myon II

This is only a quick-reference on how to build the U-Boot bootloader including Keith & Koep specific changes.
For details please view the NXP i.MX8M Mini documentation.

Get the source code of U-Boot and imx_mkimage tool from git repository:

$ mkdir uboot
$ cd uboot
~/uboot$ git clone -b kuk_imx_4.14.98_2.0.0_ga
~/uboot$ git clone -b kuk_imx_v2019.04_5.4.3_2.0.0

Setup Cross-Build environment (View Software-Development-Kit on how to install.):

$ . /opt/fsl-imx-fb/4.14-sumo/environment-setup-aarch64-poky-linux

Build U-Boot from source Code:

~/uboot/uboot-imx$ make clean
~/uboot/uboot-imx$ make myon2_defconfig
~/uboot/uboot-imx$ make all

This will generate the SPL, U-Boot and device-tree binary.
Note that this minimal device-tree binary will only be used by U-Boot and is not intended for use by the Linux kernel!
After these binaries have been created, they must be packed together with other components to form the bootloader:
SCU-Firmware: This NXP firmware is loaded into the Cortex-M4 (SCU: System Controller Unit).
ATF-Firmware: The SCU will load the ARM trusted firmware.
SPL / U-Boot: The ATF will load the primary loader, which will initialize the LPDDR4 and load U-Boot.

~/uboot/uboot-imx$ make miniflash.bin

Which will create


If you run

~/uboot/uboot-imx$ make flash_mini

this will build the bootloader and run uuu to download the bootloader to the module.

Update Bootloader using UUU

To deploy software to Myon II, you may use the NXP Universal Update Utility (UUU).
Steps needed:

Update Bootloader on Myon II running Linux

Copy bootloader (flash.bin) to a filesystem accessible by Linux.

$ dd if=/dev/zero of=/dev/mmcblk0 bs=1k seek=4096 conv=fsync count=8
$ echo 0 > /sys/block/mmcblk0boot0/force_ro
$ dd if=flash.bin of=/dev/mmcblk0boot0 bs=1k seek=33
$ echo 1 > /sys/block/mmcblk0boot0/force_ro

This will:

  • clear U-Boot environment-area,
  • disable read-only access to the boot partition,
  • write flash.bin to offset 33k and
  • reenable read-only access.

How to enter Bootloader Command Console

To enter the bootloader command console attach a serial cable to the first COM-port ( P2_TXD/RXD pins: J70-69,J70-71) with 115k2 Baud, 8N1.
Press any key while the device is powering up.
The output should look something like this:

U-Boot SPL 2018.03-00063-g076c240b55-dirty (Oct 15 2019 - 14:56:24 +0200)
DDRINFO: start lpddr4 ddr init
DDRINFO: ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from MMC1

U-Boot 2018.03-00063-g076c240b55-dirty (Oct 15 2019 - 14:56:24 +0200)

CPU:   Freescale i.MX8MMQ rev1.0 1800 MHz (running at 1200 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 56C
Reset cause: POR
Model: FSL i.MX8MM EVK board
DRAM:  2 GiB
Modul: 60A20.x01xx.Hxx
This is a Keith & Koep GmbH  Myon II V1R1 running a i.MX 8M Mini Quad 1800MHz (consumer) with 2GB,32bit RAM and booting from eMMC.
IO-Voltage 1.8V
Audio WM8983

Loading Environment from MMC... OK
No panel detected: default to MIPI2HDMI
Display: MIPI2HDMI (1920x1080)
Video: 1920x1080x24
In:    serial
Out:   serial
Err:   serial

  - ATF 1cb68fa
  - U-Boot 2018.03-00063-g076c240b55-dirty

switch to partitions #0, OK
mmc0(part 0) is current device
flash target is MMC:0
Net:   none (disabled)

Warning: ethernet@30be0000 (eth0) using random MAC address - 16:89:6e:97:26:5d
eth0: ethernet@30be0000
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0


The Linux-kernel will use a Device-Tree-Binary file (.dtb) to determine how the Trizeps module is used in a system (i.e. which drivers to load).
How the device-tree is generated might depend on the used kernel-version and it is recommended to view the articles to the respective OS in this wiki.
For Linux 4.14 the device-tree files can be found at:


When building the Linux-kernel .dts source-files are converted to .dtb binary files.

kuk-myon2 Basic Device-Tree for the Myon II module itself, which is included by all other Device-Tree baseboard files
kuk-myon2-ipanm7 Myon II in i-PAN M7 panel
kuk-myon2-conxm-hdmi Myon II in ConXM baseboard using HDMI-output

When you open the u-boot command prompt and output the environment, you can determine which device-tree is used:

u-boot=> env print -a

To change this you can i.e. call:

u-boot=> env set fdt_file kuk-myon2-ipanm7.dtb
u-boot=> env save

'env save' will store this setting for subsequent boots.

Hints on using U-Boot

Enter USB Serial Download Mode

The USB Serial Download Mode (manufacturing mode) is a mode by which the i.MX8M Mini processor loads its internal ROM-firmware instead of the bootloader stored in eMMC.
It will use the USB1 port to enumerate as HID-device on a connected PC.
In this mode the NXP Universal Update Utility (UUU) can be used to deploy software.

USB Serial Download Mode is entered by setting pin J70-40 BOOT_MODE_0 to VDD_IO on boot.
On i-PAN M7 CoverLens and ConXM (formerly: dragonBase) this can be achieved by setting a switch.

Notes on eMMC Boot Partition

Whereas SD-cards got memory organized in one user-space, eMMC have two additional boot-spaces.
The spaces are often referred to as partitions. But this might be confusing, since they are not the typical partition, one would create through a partition-table/master-boot-record.
A boot-space can overlay the first megabytes of normal user-space. After the bootloader got booted, it will fade-out the boot-space and so prevent any subsequent operating-system to be able to mess with the bootloader.
When using eMMC it needs to be decided, wether to use the boot-space or the user-space for the bootloader.
Following commands may be used to switch between the different modes (this is kept after power-cycle):

//display configuration
mmc partconf 0

mmc partconf 0 1 1 0

mmc partconf 0 1 2 0

//no boot partition, the the emmc will be used like an sd card
mmc partconf 0 0 0 0

When using different tools for updating the flash-content, a situation may arise, where the bootloader is written into the „wrong“ partition – the flash-space, which is not used for booting.

If you use

sudo ./uuu -bshow emmc

to view the default-script used by uuu, you should note the line

FB: ucmd emmc partconf ${emmc_dev} ${emmc_ack} 1 0

, which will configure the eMMC to use the boot-space after it has completed the update. If you want to use the user-space simply call

mmc partconf 0 0 0 0

after running uuu or run uuu with a custom-script.

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service/linux/uboot/myon2.txt · Zuletzt geändert: 2021/09/14 09:51 von