Part Number: BEAGLEBN
Tool/software: Linux
I am working on an Ota update and I am using Beaglebone green wireless and Debian Operating system. This is A + B Redundancy update mechanism.
I am using 2 Block device mmcblk0 and mmcblk1 one being SD card and other being eMMC respectively. My lsblk output is:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
mmcblk0 179:0 0 7.4G 0 disk
`-mmcblk0p1 179:1 0 3.3G 0 part /
mmcblk1 179:8 0 3.6G 0 disk
`-mmcblk1p1 179:9 0 3.6G 0 part
mmcblk1boot0 179:16 0 2M 1 disk
mmcblk1boot1 179:24 0 2M 1 disk
mmcblk1rpmb 179:32 0 128K 0 disk
By default, if I have an os on sd card then u-boot boots from the sd card. i.e it gives boot priority to Sd card and then to the eMMC.
I have 2 Operating systems one installed on the sd card and other on the Beaglebone eMMC. ( For A + B Redundancy update )
I am using u-boot as a bootloader.
According to my understanding, MLO is the first bootloader and it initializes and loads the second bootloader u-boot. U-boot is responsible for deciding which partition to boot from and it can be configured from the u-Env.txt in /boot.
I have a doubt related to the Booting Process. I read on many forums and documentation that u-boot reads the u-Env.txt from /boot directory for setting the Environment variable which decides the partition to boot from.
I configured the uboot by adding this line to the u-Env.txt:-
bootargs=console=ttyO0,115200n8 root=/dev/mmcblk1p1 mem=128M rootwait
bootcmd=mmc rescan; fatload mmc 0 0x82000000 uImage; bootm 0x82000000
uenvcmd=boot
Right now I am booted in the mmcblk0p1 partition i.e SD card and u-boot gives priority to the sd card by default. Now I am trying to boot from eMMC when sd card is also present on the beaglebone by adding the above line in uEnv.txt. But my bone is booting from sd card ( Os is available on both eMMC and Sd card )
I am confused if I am doing it in the right way or Where I am going wrong for Configuring the uboot environment variable?
