Re: Boot on eMMC

[Gary Thomas <gary@mlbassoc.com>]

On 2015-04-15 05:55, Shanx wrote:
> I'he successfly booted from the eMMC. To do that, I've boot from the sdcard, and I have written u-boot on mmcbl3boot0 (mmcblk3 is the eMMC) using :
>
> echo 0 > /sys/block/mmcblk3boot0/force_ro
>
> dd if=uboot.imx of=/dev/mmcblk3boot0 bs=512 seek=2 skip=2
>
> (the first line ables to write on mmcblk3boot0)
>
> I've tried to write the system on the eMMC, using :
>
> dd if=rootfs.sdcard of=/dev/mmcblk3
>
> After that, I can see the rootfs in mmcblk3p2 and the kernel and dtb files in mmcblk3p1.
>
> When booting, I access to u-boot, but it can't boot because it doesn't find the kernel. But setting the bootargs with root=/dev/mmcblk3p2, and booting using a downloaded kernel
> (stored in RAM) works.

What are the commands being used to boot in U-Boot?
What are the errors?
Have you tried running these commands by hand?

The most likely problem is that U-Boot is trying to find your kernel
on the wrong MMC device.

>
> Any idea how I can use the system written on the eMMC to boot ?
>
> 2015-04-14 17:11 GMT+02:00 Gary Thomas <gary@mlbassoc.com <mailto:gary@mlbassoc.com>>:
>
>     On 2015-04-14 09:05, Otavio Salvador wrote:
>
>         On Tue, Apr 14, 2015 at 12:04 PM, Gary Thomas <gary@mlbassoc.com <mailto:gary@mlbassoc.com>> wrote:
>
>             On 2015-04-14 09:00, Otavio Salvador wrote:
>
>
>                 On Tue, Apr 14, 2015 at 11:58 AM, Gary Thomas <gary@mlbassoc.com <mailto:gary@mlbassoc.com>> wrote:
>
>
>                     On 2015-04-14 08:28, Otavio Salvador wrote:
>
>
>
>                         On Tue, Apr 14, 2015 at 11:12 AM, Shanx <shanx@legtux.org <mailto:shanx@legtux.org>> wrote:
>
>
>
>                             Hello,
>                             I've tried a lot of things, but I can't boot on eMMC. I've flashed it
>                             from
>                             u-boot, or from the system (booted from the sdcard). For exemple, I've
>                             tried
>                             : dd if=rootfs.sdcard of=/dev/mmcblk3
>                             I've also tried to flash only u-boot.imx (with dd and seek=2)
>
>                             When booting on eMMC (with the boot switch setup given on the Linux
>                             User
>                             Guide), nothing append. Any idea why ?
>
>
>
>
>                         eMMC has some details which differ from the uSD normal usage. Mainly
>                         regarding the use of Boot Partitions. So you must to write it to the
>                         boot partition otherwise it won't work.
>
>
>                     I'm not sure this is correct.  I have an i.MX6Q board which has
>                     eMMC on SD4 and SD on SD3 and I can boot from either, using the
>                     same command to install U-Boot
>                          dd if=/tmp/disk/${UBOOT_NAME} of=${DISK} seek=2 bs=512 conv=notrunc
>
>                     Maybe it's a difference in the eMMC device (mine is Sandisk SDIN5
>                     (or7)C2-32G-L)
>
>
>
>                 It depends if Boot Partition is enabled or not.
>
>
>             Is that an i.MX6 setting?
>
>
>         No; it is eMMC 4.41 (or later) one if IIRC. There are some fields
>         exposed in sysfs and also a mmc-utils package at meta-oe.
>
>
>     Interesting, I'll look at this but my boards have boot partitions:
>
>     mmc0: new high speed DDR MMC card at address 0001
>     mmcblk0: mmc0:0001 SEM32G 29.1 GiB
>     mmcblk0boot0: mmc0:0001 SEM32G partition 1 4.00 MiB
>     mmcblk0boot1: mmc0:0001 SEM32G partition 2 4.00 MiB
>     usb 1-1: new high-speed USB device number 2 using ci_hdrc
>     mmcblk0rpmb: mmc0:0001 SEM32G partition 3 4.00 MiB
>       mmcblk0: p1 p2
>       mmcblk0boot1: unknown partition table
>       mmcblk0boot0: unknown partition table
>
>     As I said, I install U-Boot directly to block 2 of the device,
>     not to any of the "boot" partitions.
>
>     --
>     ------------------------------__------------------------------
>     Gary Thomas                 |  Consulting for the
>     MLB Associates              |    Embedded world
>     ------------------------------__------------------------------
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>

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------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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