Beaglebone black not booting from SD card

General Discussion
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1

Hi, I am just starting to learn about embedded systems and linux. A friend gave me a beaglebone black to learn.
Initially, everything was fine. When I plug in the BBB to my computer, it showed up as a storage device and then I flashed an SD card with am335x-debian-11.7-iot-armhf-2023-09-02-4gb.img and used that to run my BBB. Everything was working fine.
Then out of curiosity, I wanted to try cross-compiling and I compiled kernel 5.10.65 on my ubuntu vm and transferred files to my BBB. After reboot, I lost access to the device and it does not show up as a storage device anymore even without the SD card. I tried flashing the SD card with the image that previously worked for me but that did not work either. I hooked up a UART-USB converter to get u-boot prints and this is what I saw.

U-Boot 2022.04-ge0d31da5 (Aug 04 2023 - 18:48:26 +0000)

CPU  : AM335X-GP rev 2.1
Model: TI AM335x BeagleBone Black
DRAM:  512 MiB
Reset Source: Power-on reset has occurred.
RTC 32KCLK Source: External.
Core:  150 devices, 14 uclasses, devicetree: separate
WDT:   Started wdt@44e35000 with servicing (60s timeout)
MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
Loading Environment from EXT4... ** No partition table - mmc 0 **
Board: BeagleBone Black
<ethaddr> not set. Validating first E-fuse MAC
BeagleBone Black:
BeagleBone Cape EEPROM: no EEPROM at address: 0x54
BeagleBone Cape EEPROM: no EEPROM at address: 0x55
BeagleBone Cape EEPROM: no EEPROM at address: 0x56
BeagleBone Cape EEPROM: no EEPROM at address: 0x57
Net:   eth2: ethernet@4a100000, eth3: usb_ether
Press SPACE to abort autoboot in 0 seconds
board_name=[A335BNLT] ...
board_rev=[00C0] ...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Couldn't find partition 0:2 0x82000000
Can't set block device
Couldn't find partition 0:2 0x82000000
Can't set block device
switch to partitions #0, OK
mmc0 is current device
** No partition table - mmc 0 **
Couldn't find partition mmc 0:1
gpio: pin 56 (gpio 56) value is 0
gpio: pin 55 (gpio 55) value is 0
gpio: pin 54 (gpio 54) value is 0
gpio: pin 53 (gpio 53) value is 1
switch to partitions #0, OK
mmc0 is current device
gpio: pin 54 (gpio 54) value is 1
** No partition table - mmc 0 **
Couldn't find partition mmc 0:1
Checking for: /uEnv.txt ...
** No partition table - mmc 0 **
Couldn't find partition mmc 0:1
Checking for: /boot/uEnv.txt ...
** No partition table - mmc 0 **
Couldn't find partition mmc 0:1
** No partition table - mmc 0 **
Couldn't find partition mmc 0:2
** No partition table - mmc 0 **
Couldn't find partition mmc 0:3
** No partition table - mmc 0 **
Couldn't find partition mmc 0:4
** No partition table - mmc 0 **
Couldn't find partition mmc 0:5
** No partition table - mmc 0 **
Couldn't find partition mmc 0:6
** No partition table - mmc 0 **
Couldn't find partition mmc 0:7
switch to partitions #0, OK
mmc1(part 0) is current device
Scanning mmc 1:1...
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
Scanning disk mmc@48060000.blk...
Scanning disk mmc@481d8000.blk...
Found 3 disks
No EFI system partition
BootOrder not defined
EFI boot manager: Cannot load any image
gpio: pin 56 (gpio 56) value is 0
gpio: pin 55 (gpio 55) value is 0
gpio: pin 54 (gpio 54) value is 0
gpio: pin 53 (gpio 53) value is 1
switch to partitions #0, OK
mmc1(part 0) is current device
gpio: pin 54 (gpio 54) value is 1
Checking for: /uEnv.txt ...
Checking for: /boot/uEnv.txt ...
gpio: pin 55 (gpio 55) value is 1
1769 bytes read in 3 ms (575.2 KiB/s)
Loaded environment from /boot/uEnv.txt
Checking if uname_r is set in /boot/uEnv.txt...
gpio: pin 56 (gpio 56) value is 1
Running uname_boot ...
loading /boot/vmlinuz-5.10.65-ti-r23 ...
10347008 bytes read in 659 ms (15 MiB/s)
debug: [enable_uboot_overlays=1] ...
debug: [enable_uboot_cape_universal=1] ...
debug: [uboot_base_dtb_univ=am335x-boneblack-uboot-univ.dtb] ...
uboot_overlays: [uboot_base_dtb=am335x-boneblack-uboot-univ.dtb] ...
uboot_overlays: Switching too: dtb=am335x-boneblack-uboot-univ.dtb ...
loading /boot/dtbs/5.10.65-ti-r23/am335x-boneblack-uboot-univ.dtb ...
215189 bytes read in 18 ms (11.4 MiB/s)
Found 0 extension board(s).
uboot_overlays: [fdt_buffer=0x60000] ...
uboot_overlays: unable to find [mmc 1:1 BB-ADC-00A0.dtbo]...
uboot_overlays: unable to find [mmc 1:1 BB-BONE-eMMC1-01-00A0.dtbo]...
uboot_overlays: unable to find [mmc 1:1 BB-HDMI-TDA998x-00A0.dtbo]...
debug: [console=ttyS0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk1p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 lpj=1990656 rng_core.default_quality=100 quiet] ...
debug: [bootz 0x82000000 - 0x88000000] ...
Kernel image @ 0x82000000 [ 0x000000 - 0x9de200 ]
## Flattened Device Tree blob at 88000000
   Booting using the fdt blob at 0x88000000
   Loading Device Tree to 8ffc8000, end 8ffff894 ...

I believe the problem is that there are no partitions on the SD card but i repeated the same steps as the first time. So why would it work the first time and not the second time ? Is there any way out of this ? Any help will be appreciated. Thank you

2
  1. Completely erase your sd card.
    2.If that fails try a different card
    3.There is a small console only image that is a flasher try installing it, it will update uboot.
    4.If that boots try to reinstall the other image you want to use.
  2. Worst case if that stuff does not help, go into uboot and clean out the emmc so it will be forced to reinstall everything.
3

Thanks. I tried idea 1 and it did not work. I ran into the exact same problem. No partition table - mmc 0.
I can however get into the u-boot. But how do I erase the emmc from there ? And if I do erase the emmc, what might happen next theoretically ? Since I get this ‘No partition table’ error in mmc0 while booting, where does that leave me once I erase emmc ?

4 
=>mmc dev 0
=>mmc erase 0 1000

If successful it will continuously send the letter C out the linux debug port when you reboot without an sd inserted. I am assuming you have a TTL to usb adapter.

The IoT flasher image works fine and it will set up everything for you. Just let it run and wait until the board powers it’s self down. Remove sd, reboot and you will be running. It takes a while for it to format and then write, the blue leds will be strobing as it is writing.

5

Hi, thanks. that worked fine. Thanks a bunch !!

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