This means that CONFIG_SYS_REDUNDAND_ENVIRONMENT can not be enabled with CONFIG_ENV_IS_IN_FAT. I have checked the U-Boot code for dragonboard also and it has the same Kconfig.
As far as I understand “depends on”, It doesn’t turn on anything automatically and parent config can only be enabled if “depends on” config conditions are satisfied. In this case, as SYS_REDUNDAND_ENVIRONMENT depends on ENV_IS_IN_EEPROM || ENV_IS_IN_FLASH || ENV_IS_IN_MMC || ENV_IS_IN_NAND || ENV_IS_IN_SPI_FLASH || ENV_IS_IN_UBI, It can not be enabled untill one of this option is enabled. AFAIK, Automatic enablement is the property of ‘select’ and not ‘depends on’ in Kconfig.
I have verified that 'depends on ’ is indeed working this way. Basically SYS_REDUNDAND_ENVIRONMENT is not selectable in U-Boot menuconfig until one of the dependable config is enabled.
that sounds like a bug to me then … it used to be possible to use both together and in fact the header bytes this adds to the env file are required … (at least in UC16 and 18 … as i said, UC20 was completely re-designed without my involvement)