U-boot with redundant environment, fw_setenv does not update both environments

Question

why fw_setenv tool set value of variable only for one environment?

I am using uboot with redundant env (#define CONFIG_ENV_OFFSET 0xc0000, #define CONFIG_ENV_OFFSET_REDUND 0x100000 ), and I am going to set value of uboot env variable from linux. There is fw_setenv/fw_printenv tool which can do this:

# fw_printenv rootfs
rootfs=mtd6
# fw_setenv rootfs mtd7

Check that it is realy was set:

# fw_printenv rootfs
rootfs=mtd7

Seems OK, but after reboot system and entering to u-boot console, the value of rootfs variable is former. uboot read former value:

=> printenv
rootfs=mtd6

Then I have looked at the hexdump output of mtd devices where uboot envs placed.

Before setting rootfs mtd7:

# hexdump -C /dev/mtd3 | head -n 200

. . . . .
000000a0  65 6c 61 79 3d 35 00 62  61 75 64 72 61 74 65 3d  |elay=5.baudrate=|
000000b0  31 31 35 32 30 30 00 72  6f 6f 74 66 73 3d 6d 74  |115200.rootfs=mt|
000000c0  64 36 00 00 ff ff ff ff  ff ff ff ff ff ff ff ff  |d6..............|
000000d0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

Here rootfs=mtd6, seems OK.

# hexdump -C /dev/mtd4 | head -n 200

. . . . . 
00000090  6f 66 66 3b 20 62 6f 6f  74 6d 00 62 6f 6f 74 64  |off; bootm.bootd|
000000a0  65 6c 61 79 3d 35 00 62  61 75 64 72 61 74 65 3d  |elay=5.baudrate=|
000000b0  31 31 35 32 30 30 00 00  00 ff ff ff ff ff ff ff  |115200..........|
000000c0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

There is no rootfs variable defined in env on redundant part. Why??

After using fw_setenv rootfs mtd7

# hexdump -C /dev/mtd3 | head -n 200

000000a0  65 6c 61 79 3d 35 00 62  61 75 64 72 61 74 65 3d  |elay=5.baudrate=|
000000b0  31 31 35 32 30 30 00 72  6f 6f 74 66 73 3d 6d 74  |115200.rootfs=mt|
000000c0  64 36 00 00 ff ff ff ff  ff ff ff ff ff ff ff ff  |d6..............|
000000d0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

The environment on mtd3 stay unchanged (rootfs=mtd6).

# hexdump -C /dev/mtd4 | head -n 200

000000a0  65 6c 61 79 3d 35 00 62  61 75 64 72 61 74 65 3d  |elay=5.baudrate=|
000000b0  31 31 35 32 30 30 00 72  6f 6f 74 66 73 3d 6d 74  |115200.rootfs=mt|
000000c0  64 37 00 00 ff ff ff ff  ff ff ff ff ff ff ff ff  |d7..............|
000000d0  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|

The new rootfs variable has been wrote on mtd4.

So the content in the uboot environments is not the same. How to properly set env from linux?

Answer 1

I believe you may have wrong info in "Device offset" column of fw_env.config file, you may try

/dev/mtd6    0x0c0000       0x10000     0x10000            0x1
/dev/mtd7    0x1c0000       0x10000     0x10000            0x1
#MTDdevname  Device offset  Env. size   Flash sector size  Number of sectors

The last three columns' info may be different for your platform.