diff --git a/core/config.mk b/core/config.mk
index 4d7cd16ce..347dd2684 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -725,6 +725,7 @@ BRILLO_UPDATE_PAYLOAD := $(HOST_OUT_EXECUTABLES)/brillo_update_payload
 DEXDUMP := $(HOST_OUT_EXECUTABLES)/dexdump2$(BUILD_EXECUTABLE_SUFFIX)
 PROFMAN := $(HOST_OUT_EXECUTABLES)/profman
 HIDDENAPI := $(HOST_OUT_EXECUTABLES)/hiddenapi
+CLASS2GREYLIST := $(HOST_OUT_EXECUTABLES)/class2greylist
 
 FINDBUGS_DIR := external/owasp/sanitizer/tools/findbugs/bin
 FINDBUGS := $(FINDBUGS_DIR)/findbugs
diff --git a/core/definitions.mk b/core/definitions.mk
index 8c3a32048..61d9999d3 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2866,6 +2866,16 @@ $(INTERNAL_PLATFORM_HIDDENAPI_PRIVATE_LIST): \
     PRIVATE_DEX_INPUTS := $$(PRIVATE_DEX_INPUTS) $(1)
 endef
 
+# Generate a greylist.txt from a classes.jar
+define hiddenapi-generate-greylist-txt
+$(2): $(1) $(CLASS2GREYLIST)
+	$(CLASS2GREYLIST) $(1) > $(2)
+
+$(INTERNAL_PLATFORM_HIDDENAPI_LIGHT_GREYLIST): $(2)
+$(INTERNAL_PLATFORM_HIDDENAPI_LIGHT_GREYLIST): \
+    PRIVATE_GREYLIST_INPUTS := $$(PRIVATE_GREYLIST_INPUTS) $(2)
+endef
+
 # File names for intermediate dex files of `hiddenapi-copy-soong-jar`.
 hiddenapi-soong-input-dex = $(dir $(1))/hiddenapi/dex-input/classes.dex
 hiddenapi-soong-output-dex = $(dir $(1))/hiddenapi/dex-output/classes.dex
diff --git a/core/java.mk b/core/java.mk
index 2f85bb04d..431cae834 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -79,6 +79,7 @@ built_dex_intermediate := $(intermediates.COMMON)/dex/classes.dex
 built_dex_hiddenapi := $(intermediates.COMMON)/dex-hiddenapi/classes.dex
 full_classes_stubs_jar := $(intermediates.COMMON)/stubs.jar
 java_source_list_file := $(intermediates.COMMON)/java-source-list
+greylist_txt := $(intermediates.COMMON)/greylist.txt
 
 
 ifeq ($(LOCAL_MODULE_CLASS)$(LOCAL_SRC_FILES)$(LOCAL_STATIC_JAVA_LIBRARIES)$(LOCAL_SOURCE_FILES_ALL_GENERATED),APPS)
@@ -535,6 +536,13 @@ $(built_dex_intermediate): $(full_classes_proguard_jar) $(DX) $(ZIP2ZIP)
 endif
 
 ifneq ($(filter $(LOCAL_MODULE),$(PRODUCT_BOOT_JARS)),) # is_boot_jar
+  # Derive API greylist from the classes jar.
+  # We use full_classes_proguard_jar here, as that is what is converted to dex
+  # later on. The difference is academic currently, as we don't proguard any
+  # bootclasspath code at the moment. If we were to do that, we should add keep
+  # rules for all members with the @UnsupportedAppUsage annotation.
+  $(eval $(call hiddenapi-generate-greylist-txt,$(full_classes_proguard_jar),$(greylist_txt)))
+  LOCAL_INTERMEDIATE_TARGETS += $(greylist_txt)
   $(eval $(call hiddenapi-copy-dex-files,$(built_dex_intermediate),$(built_dex_hiddenapi)))
   built_dex_copy_from := $(built_dex_hiddenapi)
 else # !is_boot_jar
diff --git a/core/soong_java_prebuilt.mk b/core/soong_java_prebuilt.mk
index aad4b31f3..44b4f5c33 100644
--- a/core/soong_java_prebuilt.mk
+++ b/core/soong_java_prebuilt.mk
@@ -19,6 +19,7 @@ full_classes_jar := $(intermediates.COMMON)/classes.jar
 full_classes_pre_proguard_jar := $(intermediates.COMMON)/classes-pre-proguard.jar
 full_classes_header_jar := $(intermediates.COMMON)/classes-header.jar
 common_javalib.jar := $(intermediates.COMMON)/javalib.jar
+greylist_txt := $(intermediates.COMMON)/greylist.txt
 
 $(eval $(call copy-one-file,$(LOCAL_PREBUILT_MODULE_FILE),$(full_classes_jar)))
 $(eval $(call copy-one-file,$(LOCAL_PREBUILT_MODULE_FILE),$(full_classes_pre_proguard_jar)))
@@ -86,6 +87,11 @@ ifdef LOCAL_SOONG_DEX_JAR
   ifneq ($(LOCAL_UNINSTALLABLE_MODULE),true)
     ifndef LOCAL_IS_HOST_MODULE
       ifneq ($(filter $(LOCAL_MODULE),$(PRODUCT_BOOT_JARS)),)  # is_boot_jar
+        # Derive greylist from classes.jar.
+        # We use full_classes_jar here, which is the post-proguard jar (on the basis that we also
+        # have a full_classes_pre_proguard_jar). This is consistent with the equivalent code in
+        # java.mk.
+        $(eval $(call hiddenapi-generate-greylist-txt,$(full_classes_jar),$(greylist_txt)))
         $(eval $(call hiddenapi-copy-soong-jar,$(LOCAL_SOONG_DEX_JAR),$(common_javalib.jar)))
       else # !is_boot_jar
         $(eval $(call copy-one-file,$(LOCAL_SOONG_DEX_JAR),$(common_javalib.jar)))