Hi all
I am playing rauc ,and need fw_printenv and fw_setenv to switch rootfs
I put my Qz here:
https://community.nxp.com/t5/i-MX-Processors/I-can-not-build-u-boot-fw-utils-in-yocto-for-maaxboard-...
now I can build fw_printenv and fw_setenv in my yocto image.
my sd card partation is like that using file imx-uboot-bootpart.wks
uboot image is in from 33k offset to write in sdcard(that is dos)
boot partition is from offset 4M and size is 16M, ext4, will write kernel image ,dtb and uEnv.txt ...
# - --------- -------------- --------------
# |.............. | u-boot | boot | rootfs |
# - --------- -------------- --------------
# ^ ^ ^ ^
# |...............| .. |. |
# 0............33kiB 4MiB 16MiB + rootfs + IMAGE_EXTRA_SPACE (default 10MiB)
#
part u-boot --source rawcopy --sourceparams="file=imx-boot-imx8mqevk-sd.bin" --ondisk mmcblk0 --no-table --align 33
part /boot --source bootimg-partition --ondisk mmcblk0 --fstype=vfat --label boot --active --align 4096 --size 16
part / --source rootfs --ondisk mmcblk0 --fstype=ext4 --label root_A --align 4096 --overhead-factor 1
part / --source rootfs --ondisk mmcblk --fstype=ext4 --label root_B --align 4096 --overhead-factor 1
,,
I follow the guide here:
https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Linux-fw-printenv-fw-setenv-to-access-U-...
in the "demo image layout" page shows it seems the env should be write in boot partition.
but in uboot config .h file CONFIG_ENV_OFFSE 0x400000, it seems the offset is base 0, so the position is from absolute 0x400000, and it seem it is in uboot partition?
I was confused!
after uboot startup and I push CTL+C to enter it and use saveenv to save the environment variable, but It will demage my boot partition that kernel image ,dtb... files are in here. so I can not boot kernel again.
my Question is that where boot environment should be written in ? there are choices:
1, the spare space after u-boot image in uboot partition?
2 boot partition?
3. roofs partition?
and
how to calculation the CONFIG_ENV_OFFSET ? so I can set /etc/fw_env.config correctly.
any help?
Thank you very much.
,,,
fw_env.config default directory is in the /etc/
/dev/mmcblk0 0x400000 0x1000
uboot/include/configs/imx8qxp_mek.h
0x2000 : #define CONFIG_ENV_SIZE. 0x2000
#define CONFIG_ENV_OFFSET (64 * SZ_64K)
