diff --git a/src/init/CMakeLists.txt b/src/init/CMakeLists.txt
index 91c8bb5d9a61..a5799d4c476d 100644
--- a/src/init/CMakeLists.txt
+++ b/src/init/CMakeLists.txt
@@ -1,5 +1,17 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
+if(CONFIG_SOF)  ### Zephyr ###
+
+
+zephyr_library_sources(
+	init.c
+	ext_manifest.c
+)
+
+
+else()  ### Not Zephyr ###
+
+
 add_local_sources(sof init.c)
 
 add_library(ext_manifest STATIC "")
@@ -21,3 +33,6 @@ sof_append_relative_path_definitions(ext_manifest)
 
 target_link_libraries(ext_manifest sof_options)
 target_link_libraries(sof_static_libraries INTERFACE ext_manifest)
+
+
+endif() # Zephyr
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 37a51de920d9..418e5903b270 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -1,7 +1,7 @@
-# This is still WIP - Not fully validated on any platform.
-
 # When west is installed, Zephyr's CMake invokes west to list and try to
-# compile every Zephyr module that can be found.
+# compile every Zephyr module that can be found. See
+# sof/zephyr/module.yml and
+# https://docs.zephyrproject.org/latest/develop/modules.html
 if(CONFIG_SOF)
 
 if(CONFIG_LIBRARY)
@@ -114,6 +114,14 @@ zephyr_include_directories(
 # SOC level sources
 # Files that are commented may not be needed.
 
+
+# New, "de-centralized Zephyr" way. Requires "if(CONFIG_SOF)" conditionals in
+# the decentralized CMakeLists.txt files shared with XTOS.
+add_subdirectory(../src/init/ unused_install_init/)
+
+
+# Old way below: all .c files added by this giant file.
+
 # Intel TGL and CAVS 2.5 platforms
 if (CONFIG_SOC_SERIES_INTEL_CAVS_V25)
 
@@ -344,8 +352,6 @@ zephyr_library_sources(
 	${SOF_AUDIO_PATH}/pipeline/pipeline-xrun.c
 
 	# SOF core infrastructure - runs on top of Zephyr
-	${SOF_SRC_PATH}/init/init.c
-	${SOF_SRC_PATH}/init/ext_manifest.c
 	${SOF_SRC_PATH}/arch/xtensa/drivers/cache_attr.c
 	${SOF_SRC_PATH}/schedule/zephyr_domain.c
 	${SOF_SRC_PATH}/schedule/schedule.c