This article describes how to use the Preempt-RT Linux kernel in the i.MX Linux BSP 6.6.23_2.0.0. This is particularly useful for platforms such as i.MX 95, for which there is not yet a Real-Time Edge Software release.    How to do it    1. Follow the steps in the i.MX Yocto Project User's Guide and build your preferred image, for example core-image-minimal. Will further assume that the BSP is in the ~/imx-yocto-bsp directory and the build directory is ~/imx-yocto-bsp/build. 2. Unpack the attached archive in ~/imx-yocto-bsp/sources. This should create the ~/imx-yocto-bsp/sources/meta-otherkernels directory. This archive will work out of the box for i.MX 95 and i.MX 93, and may require some modifications for other platforms, as described below. 3. Add the meta-otherkernels to your build using the following command: bitbake-layers add-layer ~/imx-yocto-bsp/sources/meta-otherkernels 4. Add the OVERRIDES .= ":preempt-rt" to ~/imx-yocto-bsp/build/conf/local.conf file using the following command: echo 'OVERRIDES .= ":preempt-rt"' >> ~/imx-yocto-bsp/build/conf/local.conf This enables the Preempt-RT kernel for your build. You can always go back to your regular kernel by removing this line from ~/imx-yocto-bsp/build/conf/local.conf. 5. Build again your image. After booting this image, you can check the kernel version using: uname -a      How it works    The meta-otherkernels layer contains a .bbappend  for the linux-imx kernel recipe which replaces the sources URL with the Real-Time Edge kernel when the "preempt-rt" override is active. In addition, due to the fact that the current real-time kernel does not support all the board configurations, the layer config file (meta-otherkernels/conf/layer.conf) removes from the build the device tree files that are not supported (when "preempt-rt" override is active).   If you use this layer for other SoCs (other than i.MX 93/i.MX 95), you may need to edit the meta-otherkernels/conf/layer.conf and add the unsupported device trees. If an  unsupported device tree is left, Yocto will give an error during build.        *** DISCLAIMER *** Any support, information, and technology (“Materials”) provided by NXP are provided AS IS, without any warranty express or implied, and NXP disclaims all direct and indirect liability and damages in connection with the Material to the maximum extent permitted by the applicable law. NXP accepts no liability for any assistance with applications or product design. Materials may only be used in connection with NXP products. Any feedback provided to NXP regarding the Materials may be used by NXP without restriction.

current bsp fixed the lvds pixel clock up to 74.25Mhz for single channel and 148.5Mhz for dual channel, if customer wants to know why and how to change it, maybe can refer to the enclosed file, hope helpful for you

目录 1 i.MX8X 板级开发包镜像结构 ...................................... 3 2 创建 i.MX8QXP Linux 4.19.35 板级开发包编译环境 ... 3 2.1 下载板级开发包 ....................................................... 3 2.2 创建yocto编译环境: ................................................. 4 2.3 独立编译 ............................................................... 10 3 i.MX8X SC firmware ................................................. 16 3.1 SC firmware 目录结构 ........................................... 16 3.2 SC firmware 启动流程 ........................................... 17 3.3 SC firmware定制 ................................................... 17 4 i.MX8X ATF .............................................................. 28 5 FSL Uboot 定制 ........................................................ 30 5.1 FDT支持 ............................................................... 31 5.2 DM(driver model)支持 ........................................... 36 5.3 Uboot目录 结构 ..................................................... 50 5.4 Uboot编译 ............................................................. 52 5.5 Uboot初始化流程 .................................................. 53 5.6 uboot 定制 ............................................................ 63 5.7 uboot debug信息 ................................................... 78

In Chinese Twitter: Sino Weibo, one famous distributor mentioned “i.MX28 is the best choice in ARM9 core-based processor, no ‘one of’”. With high integration of analog module and digital module, i.MX28 is attracting more and more engineers in various applications. Despite its advantage, there are some mistakes one may commit or issues they may meet. The note records a number of issues/mistakes. Each case in the note comes from a real story. I hope the note will help you in your development work. And It is definitely welcomed for everyone to add your own content to the note.The more you share, the more you get.

目录 1    硬件资源，文档及工具下载... 2 1.1    硬件资源... 2 1.2    内存配置测试相关的文档... 3 1.3    内存压力测试工具. 3 1.4    内存配置工具. 4 2    内存设计要求... 4 3    LPDDR4基础... 4 4    硬件连接... 6 5    i.MX8QXP/DXP+LPDDR4内存配置与测试步骤... 8 5.1    生成LPDDR4初始化脚本... 8 5.2    使用内存测试工具测试内存... 13 5.3    编译内存测试工具所用的SCFW镜像... 17 5.4    其它尺寸的LPDDR4配置... 18 6    i.MX8DX+DDR3L内存配置... 23 7    测试失败的DEBUG.. 26 8    内存参数应用到SCFW中... 30

Important: If you have any questions or would like to report any issues with the DDR tools or supporting documents please create a support ticket in the i.MX community. Please note that any private messages or direct emails are not monitored and will not receive a response.   This is a detailed programming aid for the registers associated with MMDC initialization. The last sheet formats the register settings for use with ARM RealView ICE. It can also be used with the windows executable for the DDR Stress Test. This programming aid was used for internal NXP validation boards.

This page describes how to determine the NAND timing parameters for use in the NAND driver. This is independent of any OS that may be used. Analyzing NAND Datasheets  We use a spreadsheet to capture and analyze NAND features. That spreadsheet is [attached to this wiki page|Adding support for a new NAND with i.MX28– Nand Analysis^nand_analysis_template.xls]. We analyze a NAND as described below. We must have the NAND datasheet to do the analysis. Copy the *analysis spreadsheet* to a new filename with the exact part number(s) of the NAND(s) being analyzed. Fill in sheet 1 ("Cover Page") of the analysis spreadsheet. Work on sheet 3 next: Fundamental Features. Other tables. If the NAND is one of a family listed together in a data sheet, then analyze the whole family with one spreadsheet. You can use the "Similar to" rows for the additional members of the family. Add more rows if needed. Most NANDs have an asyncrhronous interface, so there is not a simple clock frequency involved. Instead, there are various setup times, hold times, and output delays that imply limits on the I/O rate to/from the NAND. The spreadsheet compares the NAND's timing specifications to see if sums of the setup, hold, and output times are shorter than the minimim read-cycle or write-cycle times. The spreadsheet is specifically intended for use with the Nand controller in STMP378x/i.MX233/i.mx28 chips, so the spreadsheet performs the timing calculations with the goal of deriving the timing parameters *TSU*, *TDS*, and *TDH* for those CPUs. If the TDS and/or TDH quantities {color:#ff0000}turn red{color} after all the timings have been computed, then the computed TDS and/or TDH are too short for the specified cycle-time of the NAND. In that case:           You will have to increase one or both of them in the software. Write a note somewhere in the analysis spreadsheet about the values that you choose, but don't mess up the automatic computations. Record how the flash denotes factory-marked bad-blocks. (Some use the first page of a block, some use the last page,, etc.) Compare it to this [current superset of bad-block marking methods [http://wiki.freescale.net/display/PSGSW/Storage+Media%2C+Flash+Bad+Block+Marks] used to detect any flash factory bad block. Example Analysis Examples of NAND datasheets and analyses can be found on the [Hynix NAND Page | http://wiki.freescale.net/display/PSGSW/Hynix+NAND+Flash+Documents].

Question: What’s the best way to rotate a MX6 image 90 degrees, thought the IPU correct? IPU is limited to 1024x1024. Apparently we don’t support frame buffer rotation in the IPU, so we have to use some middleware. I know that Android’s surface flinger uses the GPU but do you know what we can use in Linux that uses H/W acceleration also? It looks look like X-server can rotate only when the Vivante driver is not  loaded, which means the hardware is not implementing rotations. Answer: it should be possible to split the picture into two halves and rotate them separately. Well, two halves if you can reduce the line count to 1024 … otherwise it would be 4 rotates. X11 Xrandr will be implemented on GPU sometime this year. It's in the R&D queue but as low priority. They could use GC320 low level API to rotate (if they use linux frame buffer). It implies a blit but it would be done by GC320 they will probably need to use virtualFB too. The API documentation is the BSP documentation (iMX6.2D.API.pdf) Attached a simple source using the 2D low level API. VirtualFB: https://community.freescale.com/message/289198

The i.MX 6 Android 13.4.1.03 patch release is now available on www.freescale.com IMX6_R13.4103_ANDROID_LDO_PATCH This patch release is based on the i.MX6 Android R13.4.1 release. The purpose of this patch release is to manage the LDO and PMIC ramp-up time correctly.

How to add Ethernet UI support in ICS     How to add Ethernet UI support in ICS 1.  Introduction 2.  New feature detail   1.  Introduction   If you want to add Ethernet UI support , you need manually apply the attached patches in this file which is based on Android ICS and i.MX6.        About what the patches do, here is some comments: framework/base-----0001-ENGR00220371-Ethernet-add-support-for-ethernet.patch        By default, Android has no support for Ethernet UI. So if you want to add Ethernet UI , add Ethernet state tracker & Ethernet service & Ethernet manager & Ethernet monitor like WiFi. Meanwhile we need add Ethernet display support in status bar. Here this patch can solve it. Build---0001-ENGR00220371-Ethernet-add-ethernet-support.patch        add package directory compile. packages\apps\Settings---0001-ENGR00220371-Ethernet-add-app-UI-in-setting.patch        add UI logic in setting app. packages\providers\DownloadProvider---0001-ENGR00220371-Ethernet-add-downloadinfo.patch        add ConnectivityManager.TYPE_ETHERNET type support in download provider’s DownloadInfo.   2.  New feature detail   After applying the above patches, you will get the following features: Icon for Ethernet connection status. If on, a green icon will appear in status bar; If off,no icon will appear.     Add “Ethernet configuration” UI.  Choose box is designed for turn on or off Ethernet.      Only Ethernet is turned on, Ethernet configuration can be configured static IP.   First boot, Ethernet device default may not be eth0. So change it from the device list. Use imx6-ics-ethernet-v3.zip. It has updated and fixed the following issues compared with the previous two versions:   1. fix static IP not work issue. 2. fix dns using default 8.8.8.8 issue. 3. eth0 is the default interface, no longer need to choose it from the list. 4. dhcp is default mode. and if you are using static IP. After reboot, it will restore to dhcp again. 5. no need to edit dns again.   List the bug list for update. If using ethernet as upstream type, you need to apply the attached fix-use-ethernet-as-upstream.patch.   For JB4.2.2 and JB4.3, we have written one apk for this. Anyone who is interested in this can get it.

Legacy Interrupts in PCI have become a thing of the past in the PCI world, now that we have more efficient MSI interrupts in PCI Express, being used extensively across applications. However they are still used primarily for backward compatibility and boot-up support. Legacy Interrupts[INTx] used to be physical signals in PCI, however PCIe devices do not have physical INTx pins. So to support these legacy interrupts, PCIe emulates them logically. Almost like a virtual INTx mechanism. We shall see how these interrupts are realized in PCI Express, in such a way that developers/enthusiasts can get a hands-on following this guide. This blog has the following agendas:- 1. Why do we need to care about Legacy INTx style interrupts in PCIe? 2. System Overview 3. How are INTx legacy interrupts realized in PCIe? 4. Enabling and testing INTx emulation on iMX8MM

Hello! In this post, we’ll cross-compile a kernel module for Linux 6.12.    This can be done either using a standalone kernel or a Yocto-built kernel.    Requirements:  A compiled Linux kernel 6.12.  A board running the same kernel version (Linux 6.12 in this case).  A cross-compiler toolchain.    This process applies to any i.MX processor, including i.MX8, i.MX8M, i.MX8MM, i.MX8MN, i.MX8MP, i.MX93, i.MX91, i.MX95, as well as the i.MX6 and i.MX7 families.    Step 1: Compile the Linux Kernel and get the Toolchain    First, you need to compile the Linux kernel (6.12 in this case).    You can do this in a standalone environment or using Yocto.     If you are using a Standalone environment, please refer to the Chapter 4.5.12 How to build U-Boot and Kernel in standalone environment of i.MX Linux User's Guide.  Also, in that document section, you will see how to obtain the cross-compiler toolchain.    NOTE: To get the toolchain you need use Yocto at least once (for more information please refer to i.MX Yocto Project User's Guide😞  $ DISTRO=fsl-imx-xwayland MACHINE=Target-Machine bitbake core-image-minimal -c populate_sdk   At the end of the building, you can install your toolchain populated under:    yocto-bsp/build/tmp/deploy/sdk     There you will find a file called:    fsl-imx-wayland-glibc-x86_64-imx-image-core-armv8a-your-machine-name-toolchain-6.12-walnascar.sh    Execute with:  $ sudo ./fsl-imx-wayland-glibc-x86_64-imx-image-core-armv8a-your-machine-name-toolchain-6.12-walnascar.sh   If you use the default installation, you will have your toolchain under /opt in your host machine.      (If you will use the compiled kernel from Yocto, you can avoid below step)  Download Standalone Kernel source by cloning with:  $ git clone https://github.com/nxp-imx/linux-imx -b lf-6.12.y $ cd linux-imx   To build the kernel in the standalone environment for i.MX 6 and i.MX 7, execute the following commands:    $ make imx_v7_defconfig $ Make   To build the kernel in the standalone environment for i.MX 8 and i.MX 9, execute the following commands:  $ make imx_v8_defconfig $ make   The full kernel compilation is required to generate headers and symbol files required for external module compilation, even if you don't plan to boot this kernel directly.      Step 2: Write a simple Kernel Module to test    Now that your kernel is compiled, you can write a basic kernel module for testing.    Create a new directory. It will have our hello.c and Makefile.    We will create the file hello.c:  #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Salas"); MODULE_DESCRIPTION("A simple kernel module example for cross-compilation."); MODULE_VERSION("0.1"); static int __init hello_init(void) { printk(KERN_INFO "Hello from the kernel module!\n"); return 0; } static void __exit hello_exit(void) { printk(KERN_INFO "Goodbye from the kernel module!\n"); } module_init(hello_init); module_exit(hello_exit);   Then, create a basic Makefile to compile the modules:    # Module name obj-m += hello.o # Build flags ldflags-y += --strip-debug # Kernel source directory (provided by Yocto) KERNEL_SRC ?= /path/to/your/compiled/kernel # Build target all: $(MAKE) -C $(KERNEL_SRC) M=$(PWD) modules # Clean target clean: $(MAKE) -C $(KERNEL_SRC) M=$(PWD) clean # Install target modules_install: $(MAKE) -C $(KERNEL_SRC) M=$(PWD) modules_install   KERNEL_SRC should be your compiled kernel from your Yocto build:   yocto-bsp/build/tmp/work/your-machine-poky-linux/linux-imx/6.12.20+git/build   Or the Standalone : path/to/linux-imx/     Step 3: Set the toolchain and compile the kernel module    Finally, we can compile the kernel module.    First, set the toolchain (in my case):  $ source /opt/fsl-imx-wayland/6.12-walnascar/environment-setup-armv8a-poky-linux   Then, compile using the makefile:  $ make   f everything goes well, at final you will have the generated files:    hello.ko hello.mod hello.mod.c hello.mod.o hello.o Makefile modules.order Module.symvers   The one we need is the hello.ko (Kernel Object).    We can check if the file was created correctly using:    $ readelf -h hello.ko ELF Header: Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 Class: ELF64 Data: 2's complement, little endian Version: 1 (current) OS/ABI: UNIX - System V ABI Version: 0 Type: REL (Relocatable file) Machine: AArch64 Version: 0x1 Entry point address: 0x0 Start of program headers: 0 (bytes into file) Start of section headers: 33992 (bytes into file) Flags: 0x0 Size of this header: 64 (bytes) Size of program headers: 0 (bytes) Number of program headers: 0 Size of section headers: 64 (bytes) Number of section headers: 41 Section header string table index: 40   We can see the Machine is AArch64 and the Type is a Relocatable file.      Step 4: Running the Kernel Object/Module in the board    Transfer the generated hello.ko file from your host machine to your board.    Then, In your board you can run with:    root@imx93evk:~# ls hello.ko root@imx93evk:~# insmod hello.ko root@imx93evk:~# dmesg | tail [ 5140.547447] Hello world from kernel! root@imx93evk:~# rmmod hello.ko root@imx93evk:~# dmesg | tail [ 5140.547447] Hello world from kernel! [ 5153.415215] Goodbye world from kernel!   I hope this can helps to you.    Best regards,  Salas. 

Important: If you have any questions or would like to report any issues with the DDR tools or supporting documents please create a support ticket in the i.MX community. Please note that any private messages or direct emails are not monitored and will not receive a response.   These are the detailed programming aids for the registers associated with MMDC DDR3 and LPDDR2 initialization for the MX6DQ SoC. The last sheet formats the register settings for use with ARM RealView ICE. It can also be used with the windows executable for the DDR Stress Test. This programming aid was used for internal NXP boards.  

This document provide an overall guide how to get started with i.MX6 development. There are several chapters: 1. how to get necessary docs from freescale website; 2. how to setup environment and build your own images;3. Hardware design consideration;4. How to get help. I hope the doc will bring you in i.MX world more easily, and hope you all have a fun in it.

i.MX6UL/ULL extend uart port and integrate SIP I2C device. Contents 1 硬件设计说明 ............................................................. 2 硬件框图 ........................................................................ 2 硬件模块设计 ................................................................. 4 IOMUX 表 ....................................................................... 8 2 编译环境搭建 ............................................................. 8 编译环境文档及镜像下载。 ............................................ 8 编译环境搭建 ............................................................... 11 3 移植BSP 到扩展串口板 ........................................... 15 Uboot 中支持新的DTB ................................................ 15 Uboot 中调试串口改成UART6 ..................................... 16 去除掉无用的驱动及其IOMUX .................................... 18 增加i.MX6UL/ULL 本身串口支持 ................................. 18 增加GPIO 输出支持（GPIO_LED） ............................ 26 增加GPIO 输入支持（GPIO_KEY） ........................... 30 增加PWM支持 ............................................................ 34 增加i.MX6UL 本身ADC 支持 ....................................... 38 修改网口驱动仅支持一个网口 ...................................... 41 增加NXP PCF8591 I2C 转ADC 芯片支持 ................... 44 增加NXP PCA9555A I2C 转GPIO 芯片支持(rework 支持) 47 增加NXP PCT2075 I2C 温度传感器芯片支持(rework 支持) 55 增加NXP PCF8563 I2C RTC 支持(rework 支持) ......... 58 增加NXP PCA9632 I2C LED控制器芯片支持(rework 支持) 65 增加CH438 EIM 转串口芯片支持(delay) ..................... 70

On behalf of Gopise Yuan. This is an update for the DRM framebuffer capture tool I used to share with the team. Some enhancement added. Might be useful for debugging some display related issues.   Some special notes: Behavior of DRM subsystem is different between L4.x and L5.x. For L4.x, you can capture the RGB buffer without any problem. But, there’s no API for YUV (multi-plane) buffer. To capture YUV, need to apply “kernel_0001-drm-Add-getfb2-ioctl_L4.14.98.patch”. For L5.x, mapping/capturing the internal buffer is not allowed by default due to security reason. A simple change in “0001-drm-enable-mapping-of-internal-object-for-debugging_L5.x.patch” can disable this guard. Capture raw data only. RGB and YUV (packed/planar, 420/422) supported. Support de-tile on “Amphion tile” (VPU, NV12 only) and “Super tile” (Vivante GPU). Please use “-t” to enable this. Other tile might not be supported. This is a static linked binary. You can run it on any ARM64 based Linux/Android system in theory (prerequisites in item #1). If you need source code, come to me.   To get more details on how to use it, use “-?” option: DRM screen capture DRM based screen capture program Usage:     ./drmfbcap [OP] [ARG] [OP] OPeration (optional):     -v Show version.     -? Show help information.     -i Show information about target DRM device only (no capture).     -t Perform de-tile for tile format.     -d DRM device to open. [ARG] should contain the path to the device node. Default: '/dev/dri/card0'     -o Output folder. [ARG] should contain the path to the output folder. Default: '.'     -p Specific plane # to capture. [ARG] should contain the plane number. If no '-p' specified, capture all planes   Example:     ./drmfbcap   Capture all planes on default DRM device.     ./drmfbcap -d /dev/dri/controlD64   Capture all planes on '/dev/dri/controlD64' device.     ./drmfbcap -p 44 -t -o /sdcard   Capture plane 44, do de-tile after capture and then output to /sdcard/.   Raw buffer capture will be done for each enabled/target plane and one file for each. Captured file will be saved to './' if not specified. --- By Gopise, 2022/08   Updated_2023_10_16: continuous capture (repeat mode) support with this link: https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/DRM-screen-capture-tool/ta-p/1725363

Hello everyone, In this document I'll explain on how to build the UUU (Universal Update Utility) using windows 10 PC. This may be useful in case of adding custom commands to run during the flash using built-in scripts, be it for debugging, fuse blowing, etc. First we need to download and install Visual Studio community, for this guide I'll use community 2019, version it is available here: https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=Community&rel=16 For workloads select Universal Windows Platform development.   When installing, make sure to select and install the Git for windows complement, at the top select Individual components, this will display a new list, scroll down to code tools and you will find Git for windows, check this box In case Visual Studio is already installed, you may open the installer again and chose modify, this will let you install the complement as well. git_selection.png After the installation is complete we may run the git commands on the power shell. Now open the windows power shell and type the following commands: git clone https://github.com/NXPmicro/mfgtools.git // clones the MFGTool (UUU) source code from the github cd mfgtools // enters the mfgtools folder we just cloned git submodule init // creates the local configuration file for the submodules git submodule update // set the submodules to the commit specified by the main repository. At this point we can edit the built in scripts to add our custom commands, for this guide I'll add the printenv uboot command at the end of the flashing process. For this I'll enter the folder mfgtools/uuu, and edit emmc_burn_all.lst with any text editor, i.e. Notepad ++, add the command FB: ucmd printenv. add_printenv.png   Save and close the editor, it is possible to add most uboot commands like for example the fuse commands to burn eFuses. Then we can now build the tool, opening msvc/uuu-static-link.sln with Visual studio, select solution uuu-static-link.sln select_solution.png   And finally build the solution: build_solution.png The executable (uuu.exe) would be at the following path: mfgtools\msvc\x64\Debug   executable.JPG Finally we run the built in script we modified and check the results. Find attached both the powershell and uboot logs, I tested this using an i.MX8MN with L5.4.47_2.2.0, running the following command: ./uuu.exe -v -b emmc_all imx-boot-imx8mnevk-sd.bin-flash_evk imx-image-full-imx8mnevk.wic Hope this may found useful for anyone trying to achieve something similar.

Introduction. In some cases, such as development stages, testing, validate flash process from zero, etc. It is needed to erase the eMMC storage device, here is described the process and the required equipment: Required equipment. i.MX93 FRDM board (this is the selected board for this post, it works for others). Debug USB-C cable. Data USB-C cable. Micro SD (16GB recommended). Personal computer. How to erase the eMMC? This method will use another boot source (Micro SD) to erase the eMMC so, it is needed to flash the Micro SD with at least the bootloader (U-boot), you can use a prebuilt image for the EVK board, it can be downloaded from the following link. But, in the case of i.MX93 FRDM board, there is no pre-built image available and needs to be build: The FRDM-IMX93 BSP release is based on i.MX SW 2024 Q3 release with Yocto Project 5.0 (Scarthgap). To build FRDM-IMX93 image from source code, please first check i.MX Yocto Project User's Guide to get familiar with Yocto project and Yocto build. Then please follow below steps to build image for FRDM-IMX93. 1. Download i.MX SW 2024 Q3 BSP Release: $ repo init -u https://github.com/nxp-imx/imx-manifest -b imx-linux-scarthgap -m imx-6.6.36-2.1.0.xml $ repo sync 2. Integrate FRDM-MX93 layer into Yocto code base: $ cd ${MY_YOCTO}/sources $ git clone https://github.com/nxp-imx-support/meta-imx-frdm.git 3. Yocto Project Setup: $ MACHINE=imx93frdm DISTRO=fsl-imx-xwayland source sources/meta-imx-frdm/tools/imx-frdm-setup.sh -b frdm-imx93 4. Build images: $ bitbake imx-image-full The flashing process can be consulted here. Once the board is flashed, we need to change the boot switches to boot from Micro SD and turn-on the board. To debug this process, we will use Tera Term terminal with the board connected from the Micro USB debug cable to the PC and select the next configuration: Screenshot 2025-06-09 123135.png Please verify that you are selecting the corresponding COM for Cortex-A debug. After boot we need to press a key, and the board will enter to U-boot. So, then we need to select the partition of the eMMC with the next command: u-boot=> mmc dev <storage device> <partition> In the case of the eMMC, the storage device corresponds to the device "0" and if the device has an image flashed into the eMMC e.g. Linux, the device will have three partitions from 0 to 2. The next command will select the eMMC and the boot partition area: u-boot=> mmc dev 0 0 switch to partitions #0, OK mmc0(part 0) is current device Depending on the device, image, etc. This partition size can vary so, we need to know how many blocks it has. We can use the next command that will let us know the max address value that is assigned to this partition by getting an error on the address that is out of the range. u-boot=> mmc read ${loadaddr} 0x7fffffff 1 MMC read: dev # 0, block # 2147483647, count 1 ... MMC: block number 0x80000000 exceeds max(0x1d5a000) 0 blocks read: ERROR Now, with this information, we are able to erase the entire partition with the next command: u-boot=> mmc erase 0 0x1d5a000 MMC erase: dev # 0, block # 0, count 30777344 ... 30777344 blocks erased: OK As mentioned before, the device has multiple partitions so, this process needs to be done in each partition Boot area Partition. User Area 1 Partition. User Area 2 Partition. But the process is the same, let's change the partition to User Area 1: u-boot=> mmc dev 0 1 switch to partitions #1, OK mmc0(part 1) is current device  Confirm the size of the partition: u-boot=> mmc read ${loadaddr} 0x7fffffff 1 MMC read: dev # 0, block # 2147483647, count 1 ... MMC: block number 0x80000000 exceeds max(0x2000) 0 blocks read: ERROR And erase it: u-boot=> mmc erase 0 0x2000 MMC erase: dev # 0, block # 0, count 8192 ... 8192 blocks erased: OK And let's finish with User Area 2 Partition: u-boot=> mmc dev 0 2 switch to partitions #2, OK mmc0(part 2) is current device u-boot=> mmc read ${loadaddr} 0x7fffffff 1 MMC read: dev # 0, block # 2147483647, count 1 ... MMC: block number 0x80000000 exceeds max(0x2000) 0 blocks read: ERROR u-boot=> mmc erase 0 0x2000 MMC erase: dev # 0, block # 0, count 8192 ... 8192 blocks erased: OK With this done, the eMMC is completely erased and you can confirm it by turning off the board, change the boot switched to eMMC, remove the SD card and turn-on the board.  Since there is not a bootable image into the boot source, the board will jump to serial download mode and you can verify connecting the USB data cable to the board and run the next command in UUU: Untitled.png Conclusion. Erasing the eMMC of the board is optional step in your development stage but also helpful for testing or system recovery (e.g. test manufacture mode). By using a Micro SD you can access to the eMMC and do all the modifications in the partitions that you want without issues. With this you can go to a clean storage state into the boot device and test a new image from scratch or test recovery methods in your design.

Introduction There are some cases where it is needed to flash the image from a removable boot source (e.g. an SD card) to another boot source (e.g. eMMC), according to our documentation this can be done via dd but this does not work in the case you would like to do all the process in the board caused by the eMMC partition structure. Required equipment. i.MX93 FRDM board (this is the selected board for this post, it works for others). Debug USB-C cable. Data USB-C cable. Micro SD (64GB memory used in this test). Personal computer. The default partition configuration for an eMMC device is as follows: eMMC default structure.png Where: - Boot areas are used for bootloader and environment configurations. - Replay-protected memory-block area (RPMB) is used to store secure data. - User area used for application data such as file system, usually divided in two or more partitions. In the case of an image, the eMMC is organized according to the next diagram: eMMC structure.png - Boot area 1 is used to store SPL and U-boot with no file system in a fixed offset according to each processor as mentioned in i.MX Linux User's Guide section 4.3 Preparing an SD/MMC card to boot. - User area partition 1 uses a FAT format where Kernel and Device Tree files are stored. - User area partition 2 is used for root file system with Ext3/Ext4 format. Exception Our documentation has a method to flash .wic image which contains all the mentioned above or each part manually using an SD card connected to a host Linux machine via dd command: sudo dd if=<image name>.wic of=/dev/sdx bs=1M && sync Or set up the partitions manually such as bootloader: sudo dd if=<U-Boot image> of=/dev/sdx bs=1k seek=<offset> conv=fsync Also, copying the kernel image and DTB file and the root file system as mentioned in i.MX Linux User's Guide. This method works for SD card since the data is stored in user area and the offset changes to burn the bootloader. This fails when we try to flash the image from SD card to eMMC. How to reproduce the issue? First, we need to erase the eMMC, here a post to achieve this task. Format boot partition of eMMC from U-boot - NXP Community How to flash image from SD card to eMMC? With the eMMC erased, we need a boot source to store and flash the image, in this case the SD card. Once the image is flashed into the Micro SD, we need to copy the necessary files such as bootloader and image. By default, our BSP has a User Area space of <>GB and we need to increase it to save the bootloader and the image, here the steps: Verify the device and partition numeration: lsblk The command to increase the size of the partition is the next: parted /dev/<storage unit> unit MiB resizepart <partition> <size in bytes> And the command to apply the changes is: resize2fs /dev/<storage and partition unit>  In this case, the device and partition we need to change is mmcblk0p2 so, the command is as follows: parted /dev/mmcblk0 unit MiB resizepart 2 10000 I increased the partition size by 10000 MB; this will be enough to store the required files. And now, we need to apply the changes: resize2fs /dev/mmcblk0p2 In the board will look like this: Screenshot 2025-07-03 123208.png Now, let's copy the bootloader and root file system in SD. In this post we will use SCP: Screenshot 2025-07-03 124054.png Now, we need to boot from SD card and run the next commands: As is mentioned in Linux User's guide, we need to flash the .wic image. This contains all the necessary data to flash the entire image but when flashing from SD card to eMMC we need to follow additional steps to unlock the partition used to store the bootloader: sudo dd if=<image name>.wic of=/dev/sdx bs=1M && sync Disable write protection: echo 0 > /sys/block/<storage and partition unit>/force_ro And flash the bootloader: dd if=<bootloader> of=/dev/<storage and partition unit> bs=1K seek=0 In the board will look like this: Screenshot 2025-07-07 161944.png With this process now it is needed to reboot the board, change boot mode switches to boot from eMMC, and the board will boot normally, the user can perform an image flashing to simplify development workflow and also an alternative to update OS without external host dependencies.      

What is LGVL? LVGL is a graphics library to run on devices with limited resources. LVGL is fully open-source and has no external dependencies, works with any modern MCU or MPU, and can be used with any (RT)OS or bare metal setup. https://lvgl.io/   What is Framebuffer? The Linux framebuffer (fbdev) is a Linux subsystem used to show graphics on a display, typically manipulated on the system console   How to write on the frame buffer? The device is listed on de device list typically "fb0" on iMX. Chavira_0-1713985008756.png   1. Stop the window manager (Weston in our BSP) $ systemctl stop weston   2. Write random data on the frame buffer with the next command: $ cat /dev/urandom > /dev/fb0   You should see colored pixels on the screen Chavira_0-1714056022934.jpeg   3. Restart the window manager. $ systemctl start weston   Chavira_1-1713985008756.png   Cross-compiling the application   1. On the host computer we will clone the LGVL repo: $ git clone https://github.com/lvgl/lv_port_linux_frame_buffer.git -b release/v8.2 $ cd lv_port_linux_frame_buffer $ git submodule update --init --recursive 2. Configure the screen resolution, rotation, and the touch input.       2.1 The resolution is configured in lines 33 and 34 of the main.c disp_drv.hor_res = 1080; disp_drv.ver_res = 1920;           2.2 Rotation configured is on lines 32 and 57 of main.c. disp_drv.sw_rotate = 3; lv_disp_set_rotation(NULL, LV_DISP_ROT_270);     2.3 The touch input is configured on line 450 of lv_drv_conf.h # define EVDEV_NAME "/dev/input/event2"   Note: In my case is on /dev/input/event2 to check the inputs use the command "evtest" Chavira_2-1713985008757.png   3. Compile the application using the command "make"   Note: To compile the application on your host computer you have to set the environment.   4. Share the file called "demo" with your board and execute it on the board with the command $ ./demo   Note: You have to stop the weston service to run the application. Chavira_1-1714056439321.jpeg Chavira_2-1714056464298.jpeg   Chavira_3-1714056470761.jpeg Chavira_4-1714056477679.jpeg Chavira_0-1714147274371.jpeg   Notes: Tested on iMX8MN EVK with BSP 6.1.36 Works on Multimedia and Full image.