For example, if a renamed option CONFIG_NEW is a bool with value "n", kconfiglib will not generate a define for it in the Kconfig file. The define (#define CONFIG_NEW 1) will only be generated if the option is "y" or "m". However the compatibility definition was always generated: #define CONFIG_OLD CONFIG_NEW. This broke the #ifdef checks which depended on the old option names.
Bootloader Support Component ============================ Overview -------- "Bootloader support" contains APIs which are used by the bootloader but are also needed for the main app. Code in this component needs to be aware of being executed in a bootloader environment (no RTOS available, BOOTLOADER_BUILD macro set) or in an esp-idf app environment (RTOS running, need locking support.)