Boot from SD Card

I am using an Apalis imx8 and an Ixora Carrier board. I would like to boot from the external SD Card for my initial development. I know about EZ Installer but I rather use the sd card for now. I am using the wic file generated by the Toradex reference yocto build and this tutorial: Boot From an SD Card / USB Stick | Toradex Developer Center

I also erased all images on the emmc so that it can fallback to the SD Card. However, after flashing the wic file to the sd card, it doesn’t boot up. It enters the recovery mode instead.

Does the wic file include the uboot image? What is the order of the boot devices? Is SD Card device one of the devices it checks?

thank you

Hi, I’m the Toradex AI Assistant. I’m in early beta, and I would appreciate your feedback.
The Toradex Support team will follow up with you shortly!


I see you’re trying to boot your Apalis iMX8 from an SD card using a wic file from the Toradex reference Yocto build but are encountering issues with the system entering recovery mode instead of booting.

The wic file should indeed include the U-Boot image along with other necessary boot components. The boot order and whether the SD card is included as one of the devices it checks can depend on the U-Boot configuration and environment settings. For the Apalis iMX8, the default boot order typically prioritizes eMMC/internal storage, but this can be adjusted in U-Boot.

Since you’ve erased all images on the eMMC, the system should attempt to boot from other available sources, including the SD card, if the boot environment is configured correctly to do so. It’s possible that the U-Boot environment settings currently do not include the SD card in the boot search order, or the wic image was not correctly flashed to the SD card.

To troubleshoot, you might want to:

  1. Verify the SD card is correctly flashed with the wic file. Ensure the flashing process completed successfully without errors.
  2. Check the U-Boot environment settings to confirm that the SD card is included in the boot search order. You can do this by stopping the boot process to enter the U-Boot command line and using the printenv command to inspect the boot order settings.
  3. If necessary, adjust the U-Boot environment settings to include the SD card in the boot search order. This might involve modifying the boot_targets environment variable or similar, depending on your specific U-Boot configuration.

Remember, while attempting to boot from an SD card is supported for development purposes, it’s recommended to use reliable storage mediums for long-term deployment due to the potential reliability issues with standard SD cards.

Best regards,
Toradex AI Assistant

Please, also check if these links can help you solve your problem:

Boot From an SD Card / USB Stick | Toradex Developer Center.

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Thanks for the response. I don’t think the boot order depends on uboot. It should depend on the iMX8 boot rom code before anything like uboot is even loaded. In the past, I’ve used imx6 by Digi which had a jumper to switch the boot order. I’m don’t know what the boot order toradex has configured on the PCB for the Apalis IMX8 quadmax. Please provide some info regarding this.


The SD Card doesn’t boot the device. I noticed that the imx-boot (uboot) file was flashed to address 0x8000 of the sd card. When I was using imx6 a while back, I remembered the offset was 0x400. I tried that but it still doesn’t boot with the sd card. thanks

Hello @dtran11,
On our modules, the boot ROM configuration bits are not available on the module’s edge connector, and they are also not connected to GPIO’s. The modules are set to boot from fuses in the factory, and the fuse configuration is set to eMMC.
Because of that, you won’t be able to put the module in boot modes other than USB boot (via the recovery pin) or the standard eMMC boot.

If you need to boot from the SD card you’ll have to use the flashed U-boot and load the image from the SD card, or load the U-Boot image via USB recovery and then load the SD card image.

Best regards,

Hi Rafael, thanks for the answer. I can work with this. Thanks