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Trying to boot imx8mm with u-boot & kernel in nor and root filesystem in eMMC.

Question asked by Brian Hutchinson on May 21, 2020
Latest reply on May 29, 2020 by Brian Hutchinson

I want to boot IMX8 Mini from internal flash without sdcard.  I have dip switches set to:



... to boot from flex spi nor flash.  I have nor flash programmed with imx-boot-imx8mmevk-fspi.bin-flash_evk_flexspi


I want to boot u-boot from nor, load kernel from nor and mount filesystem on eMMC.


I can boot u-boot from nor and mount eMMC root filesystem if sdcard is present with a yocto generated sdcard (I had to modify some environment variables to use mmc 1 instead of mmc 0 in this case).  I programmed kernel image in nor and changed u-boot environment variables to load kernel to 0x40480000 and attempt to boot it (with no sdcard) but when I do I get:

Card did not respond to voltage select!
u-boot=> mmc info
MMC Device 0 not found
no mmc device at slot 0
u-boot=> mmc dev 1
Card did not respond to voltage select!


The eMMC is mmc 1 (which is where my filesystem is) and without the sdcard inserted it appears it's not there.  If I put sdcard in, booting and mounting from eMMC works.


How can I boot from spi nor and yet have access to mmc1 (the eMMC)?


I've been looking for documentation or an example of booting imx8mm-evk from internal flash (no sdcard) and can't find anything.  I want to know how to make each of the images required and flash them manually and not with uuu as we are making custom hardware that needs to be upgraded in the field and nobody will be connecting with board via USB with UUU, it will all be over the network writing images to flash from the target itself.


Thanks for any pointers or examples.