When building projects with mcuboot on Windows, build/mcuboot/child_image_preload.cmake is created with backslash '\' instead of forward slash '/' on line 7.
# Generated file used for preloading a child image set(CMAKE_BUILD_TYPE "" CACHE INTERNAL "NCS child image controlled") set(CMAKE_VERBOSE_MAKEFILE "FALSE" CACHE INTERNAL "NCS child image controlled") set(BOARD_DIR "V:/nordic/v2.4.0/nrf/boards/arm/thingy91_nrf9160" CACHE INTERNAL "NCS child image controlled") set(ZEPHYR_TOOLCHAIN_VARIANT "zephyr" CACHE INTERNAL "NCS child image controlled") set(NCS_TOOLCHAIN_VERSION "NONE" CACHE INTERNAL "NCS child image controlled") set(WEST_PYTHON "v:\nordic\toolchains\31f4403e35\opt\bin\python.exe" CACHE INTERNAL "NCS child image controlled") set(BOARD "thingy91_nrf9160" CACHE INTERNAL "NCS child image controlled") set(OVERLAY_CONFIG "V:/nordic/v2.4.0/nrf/modules/mcuboot/tfm.conf;V:/nordic/v2.4.0/nrf/modules/mcuboot/fih_low_enable.conf;V:/nordic/v2.4.0/nrf/subsys/partition_manager/partition_manager_enabled.conf" CACHE INTERNAL "NCS child image controlled")