imx6qpsabresd boot from emmc?

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imx6qpsabresd boot from emmc?

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dluberger
Contributor V

I followed online instructions from other threads I found, which stated I needed to mount the emmc device as a usb mass storage gadget in u-boot:

ums 0 mmc 2

I determined mmc 2 from using "mmc list" in uboot and seeing the only options were mmc 0, 1, and 2, and 0 shows as a "bad mmc device" when I try to query it, and mmc 2 shows as unreadable ext4 partition, so i assumed that would be the correct device, also since mmc2 is connected to sd 4, and the sd card is sd 3 on the schematic, so that all seemed to check out.

i was able to see that the emmc device enumerated in my host computer as /dev/sdb, so i used the dd command just as i would when copying the sd card image to a regular sd card, except this time with sdb instead of mmcblk0:

sudo dd if=card.sdcard of=/dev/sdb bs=1M && sync

that exact command works perfectly fine for /dev/mmcblk0 when i have an sd card inserted in my host computer, and i've booted from that sd card on my sabre board, so i know the image is good.

I then set the switch 6 boot-cfg to 01100011 which, per the schematic, corresponds to MMC/eMMC Boot, 1-bit mode, SD4 boot.  I can't see any reason why that setting wouldn't work, and I verified the eMMC IC is definitely populated on the board. However, when I attempt to boot, I see no serial console output nor any other indication that the device is booting from eMMC.  If I switch back to the SD card, and reset the boot-cfg switches, it boots fine.

I'm guessing someone will tell me to use the MFG tool, but I really don't like that app, and it's really confusing especially to try to teach to a manufacturing tech who will be flashing my custom board after it's fabricated.  In my mind this should be as simple as doing the exact steps I mentioned above, but as I said it's not working for some reason.

One other thing: if I list the contents (after using the above dd command) with

ls mmc 2:1 and 2:2

in uboot I get the boot partition and file system partition just as I see on the SD card (i.e., i see the same output as ls mmc 1:1 and ls mmc 1:2).  This tells me the dd command worked just fine over usb.

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igorpadykov
NXP Employee
NXP Employee

Hi David

nxp supports emmc programming for sabre sd boards only using

mfg tool or uuu tool, which can be found on i.MX Software and Development Tools | NXP 

GitHub - NXPmicro/mfgtools: Freescale/NXP I.MX Chip image deploy tools. 

For options not using these tools one can look at third party resources:

https://boundarydevices.com/programming-emmc-on-i-mx6/ 

VAR-SOM-MX6 NAND Flash Burning Jethro - Variscite Wiki 

Best regards
igor
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