erase boot partition from eMMC from u-boot cmd line

[cbrust]

I need the ability to erase the boot partition and partition information from eMMC from the U-Boot command line.  There is a command in U-Boot to do this which fails when executed on the i.MX6 SaberSD Board.  That command is "mmc erase"  When this command is issued the following is printed on the U-Boot console. Could someone give me an alternative method to erasing eMMC or tell me how to fix the usage of this command?  I can do this from a booted Linux but this is not an option.

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=> mmc erase 0 0x400

MMC erase: dev # 2, block # 0, count 1024 ... Timeout waiting for DAT0 to go high!

mmc erase failed

0 blocks erased: ERROR

=>

-------------------------------

Thanks,

C

[igorpadykov]

Hi C

probably wrong sd port was selected, one can try

to select it with mmc dev, mmc info, refer to sect.4.4.1.1 Downloading

an image to MMC/SD attached Linux Guide. Also one can write emmc

with mfg tool.

Best regards

igor

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[cbrust]

Igor,

Thanks for the suggestions, but I do have the correct device selected (mmc dev 2) and  I have successfully used the MFG Tool to write eMMC as you suggested.  The heart of the issue needing o scrub eMMC from U-Boot is because we have no jumpers or DIP switches on our custom board to select a boot mode (its hardwired to eMMC due to the application). I only used the i.MX6Q SabreSD Board as my example because our custom board is based upon that reference design. The bottom line is the U-Boot mmc erase command is failing and without being able to erase the eMMC boot partition the custom board still boots into U-Boot and will not go into serial download mode. Basically, its bricked unless we de-solder resistors to create an invalid boot mode and then put them back after reloading. Not a great option.

Here's a list of the U-Boot commands and the result of each.

----------------------------------------

=> mmc list

FSL_SDHC: 0

FSL_SDHC: 1 (SD)

FSL_SDHC: 2 (eMMC)

=> mmc dev 2

switch to partitions #0, OK

mmc2(part 0) is current device

=> mmc info

Device: FSL_SDHC

Manufacturer ID: 45

OEM: 100

Name: SEM08

Tran Speed: 52000000

Rd Block Len: 512

MMC version 4.4.1

High Capacity: Yes

Capacity: 7.4 GiB

Bus Width: 8-bit

Erase Group Size: 512 KiB

HC WP Group Size: 16 MiB

User Capacity: 7.4 GiB WRREL

Boot Capacity: 2 MiB ENH

RPMB Capacity: 128 KiB ENH

=> mmc erase 0 0x400

MMC erase: dev # 2, block # 0, count 1024 ... Timeout waiting for DAT0 to go high!

mmc erase failed

0 blocks erased: ERROR

=>

Any insight on this issue is greatly appreciated.

Thanks,

C

[igorpadykov]

Hi C

seems uboot does not support operations with partitions,

suggest also post this on uboot mail list

U-Boot Info Page

Best regards

igor

[ssurowinski]

Igor, the link you provided returns:

403 Forbidden

[cbrust]

Thanks again Igor,  I've posted this to the U-Boot mailing list.  I will post an update here once I get things resolved or otherwise.