Unexpected boot behavior on i.MX6SL EVK

[kathywright]

I'm using the i.MX6SL EVK and I have the SD card in SD1.  I'm seeing that it boots from the SD card even when I have the BOOT MODE switches set for Serial Download.  I've checked that the fuses are not blown (especially BT_FUSE_SEL), though that shouldn't matter.  The only way I can make it enter serial download mode is to remove the SD card and then reset/POR.

This does not happen with SD3.

What would make it boot from SD (internal boot) when I've set BOOT MODE for serial download? 

[JorgeRama_rezRi]

Hi Kathy,

This is normal behavior. From MX6SL reference manual:

8.11 SD/MMC Manufacture Mode

When internal boot and recover boot (if enabled) failed, boot will go to SD/MMC

manufacture mode before serial download mode. In manufacture mode, one bit bus width

is used despite of the fuse setting.

In manufacture mode, SD or MMC card will be scanned on uSDHC1 and uSDHC2. If

card is detected and valid boot image is found in card, then boot image will be loaded

then executed. Pad of SD1_CD and SD2_CD are used to detect whether card is inserted.

By default, SD/MMC manufacture mode is enabled, blow the fuse of

DISABLE_SDMMC_MFG to disable it.

NOTE

Secondary boot is not supported on SD/MMC manufacture

mode.

Best regards.

Jorge.

[kathywright]

Thanks -- I had to read this several times before I realized what the problem is.  I was incorrectly assuming that Manufacture Mode is the same as (USB) Serial Download.  Is there a way to detect that this is occurring?  I don't see anything in the u-Boot log to indicate so. 

Once I know if I've missed that indicator, then I'll blow the fuse and confirm that it changes the behavior.

Is there another way to disable Manufacture Mode?

Does Manufacture Mode work only with SD cards?  I have an eMMC on SD2 with a valid uBoot on it and it doesn't boot from it unless set to Internal Boot mode.

[robby]

Here's the answer.

i.MX6: Does i.MX6 support SD/MMC Manufacture Mode?

[kathywright]

I did find this in the new release:  L3.0.35_2.1.0_docs/i.MX_6SoloLite_EVK_Linux_Release_Notes.pdf

p. 10  (it wasn't in the earlier GA release)

"This is because SD Slot1 has first priority over others which means that, if there’s SD card in Slot1, the system will boot from Slot1 regardless of the boot switch setting. If, unfortunately, the SD card (4GB VFAT) does not have the correct uboot/uImage/rootfs, boot may fail. "

I take it "boot switch setting"  refers to the BOOT_MODE  as well as the BT_CFG ?

Where is this priority set?

[robby · Accepted solution]

[kathywright]

This doesn't seem to be accessible to the community:

Access to this place or content is restricted. If you think this is a mistake, please contact your administrator or the person who directed you here.

Thanks for the response.  I'm  really interested in seeing what it says.