Frequently Asked Questions for i.MX6 Linux

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Please refer to the following sections for details

  • Getting Started / Build Instructions / To build u-boot (LBV3) (LBV5) (LBV6)
  • Customization / Building & updating u-boot manually (LBV3) (LBV5) (LBV6)


Please refer to the following sections for details

  • Getting Started / Build Instructions / To build linux kernel (LBV3) (LBV5) (LBV6)
  • Customization / Building & updating kernel/modules/dtb manually (LBV3) (LBV5) (LBV6)



In Yocto Project, it is called "boot splashscreen", please refer to the each BSP's corresponding official Yocto website (list as below) for details

  • Yocto Project Reference Manual / Other Tips. (LBV3) (LBV5) (LBV6)

SDcard image

To build from prebuilt image, please refer to the following sections for details.

  • Getting Started / Introducing BSP / Prebuilt image (LBV3) (LBV5) (LBV6)

To build from BSP, please refer to the following sections for details.

  • Getting Started / Build Instructions / To build sdcard image (LBV3) (LBV5) (LBV6)

How To Stress Test On a Linux

Perform the command as below:

stress -c 4 -i 4  -d 1 --hdd-bytes 512

How to fix sata can't be detected issue

find ahci_imx.c in kernel source code


Mark modification as below:

      // else if(IS_RSB_4411)
      // {
      //         sata_gen_phy_reg[0] = 0x059194f6;
      //         sata_gen_phy_reg[1] = 0x059194f6;
      //         sata_gen_phy_reg[2] = 0x059194f6;

This modification are sata si test value, but it may result in some sata disk can't be detected

How To Create One LIV Disk Image of SD Card

The LIV disk image of SD card is used to boot target device up and to install the entire system to on-baord eMMC.

  • Prerequisites
    1. one free loop device
    2. prewritten script, (extracted from
    3. the built sdcard image (LBV3) (LBV5) (LBV6) (e.g. fsl-image-qt5-imx6qrsb4410a1.sdcard)
    4. 5GB more available disk space for LIV disk image (e.g. 4410A1LIV6000.img & 4410A1LIV6000.img.gz)
  • Commands
$ LODEV=$(sudo losetup -f)
$ gunzip -c > ${MKSD}
$ SDCARD=fsl-image-qt5-imx6qrsb4410a1.sdcard
$ LIV=4410A1LIV6000.img
$ cp ${SDCARD} ${LIV}
$ dd if=/dev/zero of=${LIV} bs=1M seek=3700 count=0
$ echo -e "d\n2\nn\np\n2\n24576\n\nw" | sudo fdisk -u ${LIV}
$ sudo losetup -o $((24576*512)) ${LODEV} ${LIV}
$ sudo e2fsck ${LODEV}
$ sudo resize2fs ${LODEV}
$ mkdir -p ~/mnt
$ sudo mount ${LODEV} ~/mnt
$ sudo mkdir ~/mnt/{mk_inand,image}
$ sudo cp ${MKSD} ~/mnt/mk_inand/
$ sudo chmod +x ~/mnt/mk_inand/${MKSD}
$ sudo cp ${SDCARD} ~/mnt/image/
$ sudo umount ~/mnt
$ sudo losetup -d ${LODEV}
$ gzip -c9 ${LIV} > ${LIV}.gz

How To fix "SF: Unsupported DataFlash ID 40" issue

Because we will change new spi flash on new version of the hardware, if you still use the old version u-boot, it can't be recognized.

We remove the compare spi flash id mechanism in the spi flash driver.

So we can use the patch file as belowand recompile it ,then replace the u-boot binary file in our image.


How To modify u-boot env in rootfs

Just support for Winbond spi flash(JEDEC ID: 0xef:0x40:0x16)

./fw_printenv                    //print all env 
./fw_printenv [env_name]         //print specific env
  • Set env
./fw_setenv [env_name] [value]   //set new env
  • Delete env
./fw_setenv [env_name]

How To Get unique ID for iMX SOC

  • iMX6

OTP Bank0 Word1 - containsthe first word of the UID.

OTP Bank0 Word2 - contains the second word of the UID.

We can refer to iMX6 DRM Chap46.5.10

root@imx6dlebcrs03a1:~# cat /sys/fsl_otp/HW_OCOTP_CFG0
root@imx6dlebcrs03a1:~# cat /sys/fsl_otp/HW_OCOTP_CFG1

  • iMX7
cat /sys/fsl_otp/HW_OCOTP_TESTER0
cat /sys/fsl_otp/HW_OCOTP_TESTER1

  • iMX8M
root@imx8mqevk:/# cat /sys/bus/soc/devices/soc0/soc_uid

How To Rotate Screen for iMX6 (Yocto)

root@imx6dlrsb4411a1:~# export DISPLAY=:0
// rotate to the left
root@imx6dlrsb4411a1:~# xrandr -o left
// rotate to the right
root@imx6dlrsb4411a1:~# xrandr -o right
// flip
root@imx6dlrsb4411a1:~# xrandr -o inverted
// back to a normal
root@imx6dlrsb4411a1:~# xrandr -o normal

How To Support UIO-4036 board for iMX6 (Yocto 2.1)

1. Add usb ethernet driver about SMSC75XX

2. Add the rtl8368MBI lan switch driver:

3. Add the device tree setting:

Other Features