Help Needed: Flashing eMMC from SD card (BBB)

General Discussion
1

flash_eMMC.txt (3.8 KB)

I’m trying to flash a new image to my BBB. I used the BeagleBoard Imager to BeagleBone Black Debian 12 v5.10.x-ti to an SD card, and modified /boot/uEnv.txt to uncomment the line

##enable Generic eMMC Flasher:
cmdline=init=/usr/sbin/init-beagle-flasher

I held S2 button while powering on, and attached the serial output here as a file.

2

Just run:

sudo beagle-flasher

and it’ll flash the ‘other’…

Looking at your boot log, it ignored the microSD…

Regards,

3

I mounted the SD card from the BBB, and ran

debian@beaglebone:/mnt/usr/sbin$ sudo ./beagle-flasher

And I get this

--------------------------------------------------------------------------------
Version: [1.20250527.0, add new fat-swap-rootfs layout...]
--------------------------------------------------------------------------------
Example: /etc/default/beagle-flasher
--------------------------------------------------------------------------------
source=/dev/mmcblk0
destination=/dev/mmcblk1
rfs_partition=single
rfs_rootfs_type=ext4
rfs_rootfs_startmb=4
bootloader=/opt/u-boot/bb-u-boot-am335x-evm/install-mmcblk1.sh
flash_back=beaglebone-black-emmc-to-microsd

This looks right to me, but what do I know. Frankly, I’m a little confused in what context I should be executing the command.

4

it should start flashing…

What does sudo beagle-version show?

5

Took me a second to find…

root@beaglebone:/mnt/usr/bin# ./beagle-version 
eeprom:[A335BNLT00C02324SBB27824]
model:[TI_AM335x_BeagleBone_Black]
dogtag:[BeagleBoard.org Debian Buster IoT Image 2020-04-06]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot SPL 2022.04-gb4b56c73 (Oct 28 2025 - 17:45:28 +0000)]:[location: dd MBR]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot SPL 2019.04-00002-g31a8ae0206 (May 13 2020 - 09:26:17 -0500)]:[location: dd MBR]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 2019.04-00002-g31a8ae0206]:[location: dd MBR]
UBOOT: Booted Device-Tree:[am335x-boneblack-uboot-univ.dts]
UBOOT: Loaded Overlay:[AM335X-PRU-RPROC-4-19-TI-00A0]
UBOOT: Loaded Overlay:[BB-ADC-00A0]
UBOOT: Loaded Overlay:[BB-BONE-eMMC1-01-00A0]
UBOOT: Loaded Overlay:[BB-HDMI-TDA998x-00A0]
kernel:[4.19.94-ti-r42]
nodejs:[v10.15.2]
/boot/uEnv.txt Settings:
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-19-TI-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]
pkg:[bb-customizations]:[1.20200306.0-0rcnee0~buster+20200306]
pkg:[bb-usb-gadgets]:[1.20200322.0-0rcnee0~buster+20200322]
pkg:[bb-wl18xx-firmware]:[1.20200322.0-0rcnee0~buster+20200322]
pkg:[kmod]:[26-1]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal bluetooth netdev i2c gpio pwm eqep remoteproc admin spi iio docker]
cmdline:[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_co]
dmesg | grep remote
[   58.883334] remoteproc remoteproc0: wkup_m3 is available
[   58.967718] remoteproc remoteproc0: powering up wkup_m3
[   58.967751] remoteproc remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217168
[   58.968034] remoteproc remoteproc0: remote processor wkup_m3 is now up
[   61.287777] remoteproc remoteproc1: 4a334000.pru is available
[   61.290109] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[   61.287777] remoteproc remoteproc1: 4a334000.pru is available
[   61.287948] pru-rproc 4a334000.pru: PRU rproc node pru@4a334000 probed successfully
[   61.290109] remoteproc remoteproc2: 4a338000.pru is available
[   61.290286] pru-rproc 4a338000.pru: PRU rproc node pru@4a338000 probed successfully
dmesg | grep pinctrl-single
[    0.921809] pinctrl-single 44e10800.pinmux: 142 pins, size 568
dmesg | grep gpio-of-helper
[    0.935016] gpio-of-helper ocp:cape-universal: ready
dmesg | grep wlcore
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END
6

Yeah your in the eMMC..

Where you are right now, just hold the ‘usr’ button, and push the ‘reset’ button… Lift finger only after the 4 leds turn on..

Regards,

7

No, luck, it still boots from the eMMC. When I go into the u-boot console, I can see mmc0. I tried running mmc dev 0 followed by boot, but it didn’t seem to help anything either.

Could it be defaulting to the eMMC, since no boot order is specified?

When the boot button is held, a newer version of u-boot is used (2019 vs. 2022). Does that mean that the SD card is being accessed?

8

Yeap… when you see u-boot loading 2022, that means it’s booting from microSD, and it should boot first before eMMC..

Regards,

9

Okay, so I switched to an older image (AM335x 11.7 2023-09-02 4GB microSD IoT) to see if that would help. I then went into the u-boot console and selected mmc0 as the boot device, which can be seen here

=> mmc dev 0
switch to partitions #0, OK
mmc0 is current device
=> boot
board_name=[A335BNLT] ...
board_rev=[00C0] ...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
switch to partitions #0, OK
mmc0 is current device
Scanning 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
Checking for: /uEnv.txt ...
Checking for: /boot.scr ...
Checking for: /boot/boot.scr ...
Checking for: /boot/uEnv.txt ...
** Invalid partition 2 **
** Invalid partition 3 **
** Invalid partition 4 **
** Invalid partition 5 **
** Invalid partition 6 **
** Invalid partition 7 **
switch to partitions #0, OK
mmc1(part 0) is current device

It seems like it tries to boot from the sd card, fails for some reason and falls back to the emmc… Any thoughts on why?