AM3357: BeagleBone Black: can't boot from SD card having only bootloader

Here is boot log when using u-boot files, originated from u-boot build where am335x_evm_defconfig file was used as default configuration :

U-Boot SPL 2020.10-rc3-00012-g9f04a634ef (Aug 29 2020 - 11:40:17 +0200)
Trying to boot from MMC1
U-Boot 2020.10-rc3-00012-g9f04a634ef (Aug 29 2020 - 11:40:17 +0200)
CPU : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black
DRAM: 512 MiB
WDT: Started with servicing (60s timeout)
NAND: 0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment
<ethaddr> not set. Validating first E-fuse MAC
Net: eth2: ethernet@4a100000, eth3: usb_ether
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Failed to load 'boot.scr'
Failed to load 'uEnv.txt'
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Failed to load '/boot/zImage'
switch to partitions #0, OK
mmc1(part 0) is current device
Scanning mmc 1:1...
Found /boot/extlinux/extlinux.conf

The last line Found /boot/extlinux/extlinux.conf signifies, that boot process from sd-card failed and BBB switched to eMMC (where extlinux.conf indeed does exist) and then successfully boots from eMMC.

What's wrong with SD card content ?

Thanks.

Hi Hong,

Thanks.

I used script create-sdcard.sh. Works well, but along with boot files it copies also kernel.

Is it possible to copy only boot files in order to have U-boot# prompt after booting from sd-card.

Probably I have to modify some parameters while following through create-sdcard.sh options.

Here is log of the session:

pavel@ALABAMA:~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/bin$ sudo ./create-sdcard.sh
[sudo] password for pavel:

################################################################################

This script will create a bootable SD card from custom or pre-built binaries.

The script must be run with root permissions and from the bin directory of
the SDK

Example:
 $ sudo ./create-sdcard.sh

Formatting can be skipped if the SD card is already formatted and
partitioned properly.

################################################################################

Available Drives to write images to:

#  major   minor    size   name
1:   8        0   15558144 sda
 
Enter Device Number or n to exit: 1
 
sda was selected

/dev/sda is an sdx device
Unmounting the sda drives
 unmounted /dev/sda1
 unmounted /dev/sda2
Current size of sda1 65536 bytes
Current size of sda2 1048576 bytes

################################################################################

    Select 2 partitions if only need boot and rootfs (most users).
    Select 3 partitions if need SDK & other content on SD card.  This is
        usually used by device manufacturers with access to partition tarballs.

    ****WARNING**** continuing will erase all data on sda

################################################################################

Number of partitions needed [2/3] : 2

 
Now partitioning sda with 2 partitions...
 

################################################################################

        Now making 2 partitions

################################################################################

1024+0 records in
1024+0 records out
1048576 bytes (1,0 MB, 1,0 MiB) copied, 0,284389 s, 3,7 MB/s
DISK SIZE - 15931539456 bytes

################################################################################

        Partitioning Boot

################################################################################
mkfs.fat 4.1 (2017-01-24)
mkfs.fat: warning - lowercase labels might not work properly with DOS or Windows

################################################################################

        Partitioning rootfs

################################################################################
mke2fs 1.44.1 (24-Mar-2018)
Creating filesystem with 3867392 4k blocks and 967232 inodes
Filesystem UUID: d28faf5e-a76c-4221-816b-0a255a1f6a37
Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done   



################################################################################

   Partitioning is now done
   Continue to install filesystem or select 'n' to safe exit

   **Warning** Continuing will erase files any files in the partitions

################################################################################


Would you like to continue? [y/n] : y

 
 
Mount the partitions
 
Emptying partitions
 

Syncing....

################################################################################

    Choose file path to install from

    1 ) Install pre-built images from SDK
    2 ) Enter in custom boot and rootfs file paths

################################################################################

Choose now [1/2] : 1

 
Will now install from SDK pre-built images
now installing:  ti-processor-sdk-linux-am335x-evm-06.03.00.106

################################################################################

   Multiple rootfs Tarballs found

################################################################################

     1:tisdk-rootfs-image-am335x-evm.tar.xz
     2:tisdk-docker-rootfs-image-am335x-evm.tar.xz

Enter Number of rootfs Tarball: 1
 
################################################################################

    Copying files now... will take minutes

################################################################################

Copying boot partition



MLO copied


u-boot.img copied


Copying rootfs System partition
                                                                                                                

 
Syncing...
 
Un-mount the partitions
 
Remove created temp directories
 
Operation Finished
 
pavel@ALABAMA:~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/bin$

Sincerely,

Pavel.

Hi Hong,

Thanks. The only location in SDK, where I've found boot files (MLO and .img) is

~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images/

But script refuses it:

################################################################################

    Choose file path to install from

    1 ) Install pre-built images from SDK
    2 ) Enter in custom boot and rootfs file paths

################################################################################

Choose now [1/2] : 2

 

################################################################################

  For U-boot and MLO

  If files are located in Tarball write complete path including the file name.
      e.x. $:  /home/user/MyCustomTars/boot.tar.xz

  If files are located in a directory write the directory path
      e.x. $: /ti-sdk/board-support/prebuilt-images/

  NOTE: Not all platforms will have an MLO file and this file can
        be ignored for platforms that do not support an MLO.

  Update: The proper location for the kernel image and device tree
          files have moved from the boot partition to the root filesystem.

################################################################################

Enter path for Boot Partition : ~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images

Invalid path make sure to include complete path
Enter path for Boot Partition : ~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images/

Invalid path make sure to include complete path
Enter path for Boot Partition :

Where I've been mistaken ?

Sincerely,

Pavel.

Hi Hong,

Yes, it was the case.

But further it asks for kernel ... something that I don't want to install.

How to proceed ?

Sincerely,

Pavel.

Invalid path make sure to include complete path
Enter path for Boot Partition : /home/pavel/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images

Directory exists

This directory contains:
MLO-am335x-evm                  am335x-boneblack-wireless-am335x-evm.dtb  am335x-evm.dtb                  am335x-icev2.dtb
am335x-bone-am335x-evm.dtb          am335x-boneblack-wireless.dtb            am335x-evmsk-am335x-evm.dtb              am335x-pocketbeagle-am335x-evm.dtb
am335x-bone.dtb                  am335x-boneblack.dtb                am335x-evmsk.dtb                  am335x-pocketbeagle.dtb
am335x-boneblack-am335x-evm.dtb          am335x-boneblue-am335x-evm.dtb        am335x-icev2-am335x-evm.dtb              am335x-sancloud-bbe-am335x-evm.dtb
am335x-boneblack-iot-cape-am335x-evm.dtb  am335x-boneblue.dtb                am335x-icev2-pru-excl-uio-am335x-evm.dtb  am335x-sancloud-bbe.dtb
am335x-boneblack-iot-cape.dtb          am335x-bonegreen-am335x-evm.dtb        am335x-icev2-pru-excl-uio.dtb          u-boot-am335x-evm.img
am335x-boneblack-pru-adc-am335x-evm.dtb   am335x-bonegreen-wireless-am335x-evm.dtb  am335x-icev2-prueth-am335x-evm.dtb          u-boot-spl.bin-am335x-evm
am335x-boneblack-pru-adc.dtb          am335x-bonegreen-wireless.dtb            am335x-icev2-prueth-pps-am335x-evm.dtb    zImage-am335x-evm.bin
am335x-boneblack-prusuart-am335x-evm.dtb  am335x-bonegreen.dtb                am335x-icev2-prueth-pps.dtb
am335x-boneblack-prusuart.dtb          am335x-evm-am335x-evm.dtb            am335x-icev2-prueth.dtb

Is this correct? [y/n] : y


################################################################################

   For Kernel Image and Device Trees files

    What would you like to do?
     1) Reuse kernel image and device tree files found in the selected rootfs.
     2) Provide a directory that contains the kernel image and device tree files
        to be used.

################################################################################

Choose option 1 or 2 :

Hi Hong,

I proceeded as you suggested,

First I copied 2 files MLO-am335x-evm and u-boot-am335x-evm.img into boot partition on sd-card.

pavel@ALABAMA:~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images$ cp -v MLO-am335x-evm u-boot-am335x-evm.img /media/pavel/boot/
'MLO-am335x-evm' -> '/media/pavel/boot/MLO-am335x-evm'
'u-boot-am335x-evm.img' -> '/media/pavel/boot/u-boot-am335x-evm.img'
pavel@ALABAMA:~/ti-processor-sdk-linux-am335x-evm-06.03.00.106/board-support/prebuilt-images$

It doesn't work: I inserted sd-card in BBB and on Power ON I observed CCCCCCCC.. in terminal.

Then I renamed them in MLO and u-boot.img.

The initial situation (that I evoked in my 1st message) was repeated: first BBB tried to boot from SD card and, failing to boot from SD-card, has changed to eMMC.

Here is log.

Sincerely,

Pavel.

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
U-Boot SPL 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)
Trying to boot from MMC1


U-Boot 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)

CPU  : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black
DRAM:  512 MiB
NAND:  0 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment

<ethaddr> not set. Validating first E-fuse MAC
Net:   eth0: ethernet@4a100000
Warning: usb_ether MAC addresses don't match:
Address in ROM is          de:ad:be:ef:00:01
Address in environment is  94:e3:6d:d4:ae:88
, eth1: usb_ether
Hit any key to stop autoboot:  0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
** Unable to read file boot.scr **
** Unable to read file uEnv.txt **
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
** File not found /boot/zImage **
switch to partitions #0, OK
mmc1(part 0) is current device
Scanning mmc 1:1...
Found /boot/extlinux/extlinux.conf
Retrieving file: /boot/extlinux/extlinux.conf
256 bytes read in 0 ms
1:    Linux 4.19.94-ti-r42
Retrieving file: /boot/vmlinuz-4.19.94-ti-r42
10095592 bytes read in 650 ms (14.8 MiB/s)
append: console=ttyO0,115200n8 root=/dev/mmcblk1p1 ro rootfstype=ext4 coherent_pool=1M net.ifnames=0 lpj=1990656 rng_core.default_quality=100 quiet
Retrieving file: /boot/dtbs/4.19.94-ti-r42/am335x-boneblack.dtb
59483 bytes read in 6 ms (9.5 MiB/s)
## Flattened Device Tree blob at 88000000
   Booting using the fdt blob at 0x88000000
   Loading Device Tree to 8ffee000, end 8ffff85a ... OK

Starting kernel ...

[    0.000767] timer_probe: no matching timers found
[    0.115140] l4_wkup_cm:clk:0010:0: failed to disable
[    8.729927] omap_voltage_late_init: Voltage driver support not added

Debian GNU/Linux 10 beaglebone ttyS0

BeagleBoard.org Debian Buster IoT Image 2020-04-06

Support: elinux.org/Beagleboard:BeagleBoneBlack_Debian

default username:password is [debian:temppwd]

beaglebone login: debian
Password:
Last login: Tue Sep  1 10:22:54 UTC 2020 on ttyS0

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
debian@beaglebone:~$

Hi Patel,

At u-boot prompt, what is the output from

$md.l 0x44E10040 1

Best,

-Hong

Hi Hong,

The problem I can't get u-boot prompt.

As I mentioned before, when I try to boot from an SD card which only contains u-boot files (MLO and u-boot.img), on power-up (with S2 pushed) , BBB almost immediately switches to eMMC and boots from eMMC.

And finally I get Linux prompt, not u-boot prompt.

Sincerely,

Pavel.

P.S. Here is as it looks:

U-Boot SPL 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)
Trying to boot from MMC1


U-Boot 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)

CPU  : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black
DRAM:  512 MiB
NAND:  0 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment

<ethaddr> not set. Validating first E-fuse MAC
Net:   Could not get PHY for ethernet@4a100000: addr 0
eth0: ethernet@4a100000
Warning: usb_ether MAC addresses don't match:
Address in ROM is          de:ad:be:ef:00:01
Address in environment is  94:e3:6d:d4:ae:88
, eth1: usb_ether
Hit any key to stop autoboot:  0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
** Unable to read file boot.scr **
** Unable to read file uEnv.txt **
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
** File not found /boot/zImage **
switch to partitions #0, OK
mmc1(part 0) is current device
Scanning mmc 1:1...
Found /boot/extlinux/extlinux.conf
Retrieving file: /boot/extlinux/extlinux.conf
256 bytes read in 0 ms
1:    Linux 4.19.94-ti-r42
Retrieving file: /boot/vmlinuz-4.19.94-ti-r42
10095592 bytes read in 650 ms (14.8 MiB/s)
append: console=ttyO0,115200n8 root=/dev/mmcblk1p1 ro rootfstype=ext4 coherent_pool=1M net.ifnames=0 lpj=1990656 rng_core.default_quality=100 quiet
Retrieving file: /boot/dtbs/4.19.94-ti-r42/am335x-boneblack.dtb
59483 bytes read in 6 ms (9.5 MiB/s)
## Flattened Device Tree blob at 88000000
   Booting using the fdt blob at 0x88000000
   Loading Device Tree to 8ffee000, end 8ffff85a ... OK

Starting kernel ...

[    0.000762] timer_probe: no matching timers found
[    0.115132] l4_wkup_cm:clk:0010:0: failed to disable
[    8.729922] omap_voltage_late_init: Voltage driver support not added

Debian GNU/Linux 10 beaglebone ttyS0

BeagleBoard.org Debian Buster IoT Image 2020-04-06

Support: elinux.org/Beagleboard:BeagleBoneBlack_Debian

default username:password is [debian:temppwd]

beaglebone login:

I have explored two SD cards with fdisk:

• left column: full linux image, generated with create-sdcard.sh script from SDK
• right column: sd-card was prepared using this scenario (until p.3 in "Writing Boot Files to the SD Card")

As you can see physical location of boot partition is different on two cards (in bold red).

Probably the problem is here ?

Sincerely,

Pavel.

HI Patel,

At kennel prompt, what is output from

$devmem2 0x44E10040

Best,

-Hong

Hi Hong,

Here it is:

root@am335x-evm:~# devmem2 0x44E10040
/dev/mem opened.
Memory mapped at address 0xb6f29000.
Read at address  0x44E10040 (0xb6f29040): 0x00400338
root@am335x-evm:~#

By the way I also tried when booted from eMMC ...

debian@beaglebone:~$ devmem2 0x44E10040
-bash: devmem2: command not found
debian@beaglebone:~$

Sincerely,

Pavel.

Hi Pavel,

Which SW are you testing with on which board?

If you use pre-built binaries from TI SDK package, and copy only MLO/u-boot.img to boot partition of SD card, have you tried hitting any key during u-boot boot process?

FYI: in the log you posted earlier:

Hit any key to stop autoboot:  0 

Pavel Yermolenko1 said:

root@am335x-evm:~# devmem2 0x44E10040
/dev/mem opened.
Memory mapped at address 0xb6f29000.
Read at address  0x44E10040 (0xb6f29040): 0x00400338
root@am335x-evm:~#

=> SYSBOOT[4:0] = 11000b  => boot order as SPI0 MMC0 USB0 UART0, and it should work for booting from SD card.

Best,

-Hong

Yes, I've got this:

U-Boot SPL 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)
Trying to boot from MMC1


U-Boot 2019.01-g333c3e72d3 (Apr 19 2020 - 11:21:12 +0000)

CPU  : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black
DRAM:  512 MiB
NAND:  0 MiB
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment

<ethaddr> not set. Validating first E-fuse MAC
Net:   eth0: ethernet@4a100000
Warning: usb_ether MAC addresses don't match:
Address in ROM is          de:ad:be:ef:00:01
Address in environment is  94:e3:6d:d4:ae:88
, eth1: usb_ether
Hit any key to stop autoboot:  0
=> md.l 0x44E10040 1
44e10040: 00400338                               8.@.
=>

I'm not sure that I've got u-boot prompt. Anyway I've tried suggested command (i.e. md.l).

Sincerely,

Pavel.

Hi Hong,

Here in attachment, excerpt from the book Mastering Embedded Linux Programming, 2nd Ed. (By Chris Simmonds). In this excerpt, the author shows his approach how to boot from SD card, having only u-boot files (i.e. without kernel). I tried to replicate this on my BBB, but failed. I did exactly what Chris Simmonds suggested in his book. The purpose of this poste was to solve the problem of my failure where Chris Simmonds succeeded. The only difference between our cases was that Mr. Simmonds was using the v2017 branch to build u-boot while I was using the master branch. Why what was possible in 2017 is no longer possible in 2020. Also, not only in Chris Simmonds' book, but also somewhere on TI's website (I can find the link), the prompt u- boot is present as U-boot #, but not as =>. Or U-boot # is the old one, and => is it modern?

Sincerely,

Pavel

extraced_pages.pdf

Hi Hong,

Thanks.

Can you give your opinion why I did not succeed in booting from SD card where there were only 2 u-boot files ... the operation that Chris Simmonds did 3 years ago. What has changed during these 3 years?

Sincerely,

Pavel.

Hi Hong,

Yes I tried help and I'm assured that when I type at the start of boot, I switch to u-boot prompt.

But according to Chris Simmonds, if on the SD card there is no kernel (i.e. only u-boot files), the user does not need to type when powering on and the system alone manages to switch to u-boot prompt - operation I failed to reproduce.

Have you any explanation on this ?

Another issue: in his book Chris Simmonds uses some commands that I didn't find in "help" list. One of them nand command, e.g.

nand read 82000000 200000 400000

Does exist a document that compares "old" and "modern" versions of u-boot ?

Sincerely,

Pavel.

Hi Hong,

You’ll find many online reference guide covering more details on on u-boot/Linux…

PS: if your original questions are addressed, please go ahead close the e2e thread.

I really appreciated your help and your skills. The only issue (which in my opinion is closely related to this thread) that remains unresolved is:

How should BBB behave upon Power On when S2 button is pressed and on the SD card there are only 2 files in the boot partition (MLO and u-boot.img) ... without any actions from user ?

Do you consider that I can get an answer to this issue in this thread, or should I create a new one?

u-boot cmd set supported depends on how u-boot is built for specific configuration and boards etc…

Does it mean that I could find a document (probably somewhere on the web) that lists all commands of a particular release of u-boot (2017 in my case) ?

Or should I build u-boot v2017 to see its set of commands ?

Sincerely,

Pavel.

Hi Hong,

Thanks !!!

It's what I looked for.

Perhaps in the case of Chris Simmonds (2017's u-boot release) there was some option that stops at u-boot if it doesn't find kernel.

Sincerely,

Pavel.