diff --git a/core/Makefile b/core/Makefile
index a580ac8..09efca5 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -908,8 +908,14 @@
 INTERNAL_BOOTIMAGE_ARGS := \
 	$(addprefix --second ,$(INSTALLED_2NDBOOTLOADER_TARGET))
 
+INTERNAL_INIT_BOOT_IMAGE_ARGS :=
+
 ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
-INTERNAL_BOOTIMAGE_ARGS += --ramdisk $(INSTALLED_RAMDISK_TARGET)
+  ifneq ($(BUILDING_INIT_BOOT_IMAGE),true)
+    INTERNAL_BOOTIMAGE_ARGS += --ramdisk $(INSTALLED_RAMDISK_TARGET)
+  else
+    INTERNAL_INIT_BOOT_IMAGE_ARGS += --ramdisk $(INSTALLED_RAMDISK_TARGET)
+  endif
 endif
 
 ifndef BUILDING_VENDOR_BOOT_IMAGE
@@ -1089,6 +1095,58 @@
 my_installed_prebuilt_gki_apex :=
 
 # -----------------------------------------------------------------
+#  init boot image
+ifeq ($(BUILDING_INIT_BOOT_IMAGE),true)
+
+INSTALLED_INIT_BOOT_IMAGE_TARGET := $(PRODUCT_OUT)/init_boot.img
+$(INSTALLED_INIT_BOOT_IMAGE_TARGET): $(MKBOOTIMG) $(INSTALLED_RAMDISK_TARGET)
+
+ifdef BOARD_KERNEL_PAGESIZE
+  INTERNAL_INIT_BOOT_IMAGE_ARGS += --pagesize $(BOARD_KERNEL_PAGESIZE)
+endif
+
+ifeq ($(BOARD_AVB_ENABLE),true)
+$(INSTALLED_INIT_BOOT_IMAGE_TARGET): $(AVBTOOL) $(BOARD_AVB_INIT_BOOT_IMAGE_KEY_PATH)
+	$(call pretty,"Target init_boot image: $@")
+	$(MKBOOTIMG) $(INTERNAL_INIT_BOOT_IMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_INIT_ARGS) --output $@
+	$(call assert-max-image-size,$@,$(BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE))
+	$(AVBTOOL) add_hash_footer \
+           --image $@ \
+	   --partition_size $(BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE) \
+	   --partition_name init_boot $(INTERNAL_AVB_INIT_BOOT_SIGNING_ARGS) \
+	   $(BOARD_AVB_INIT_BOOT_ADD_HASH_FOOTER_ARGS)
+else
+$(INSTALLED_INIT_BOOT_IMAGE_TARGET):
+	$(call pretty,"Target init_boot image: $@")
+	$(MKBOOTIMG) $(INTERNAL_INIT_BOOT_IMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_INIT_ARGS) --output $@
+	$(call assert-max-image-size,$@,$(BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE))
+endif
+
+else # BUILDING_INIT_BOOT_IMAGE is not true
+
+ifdef BOARD_PREBUILT_INIT_BOOT_IMAGE
+INTERNAL_PREBUILT_INIT_BOOT_IMAGE := $(BOARD_PREBUILT_INIT_BOOT_IMAGE)
+INSTALLED_INIT_BOOT_IMAGE_TARGET := $(PRODUCT_OUT)/init_boot.img
+
+ifeq ($(BOARD_AVB_ENABLE),true)
+$(INSTALLED_INIT_BOOT_IMAGE_TARGET): $(INTERNAL_PREBUILT_INIT_BOOT_IMAGE) $(AVBTOOL) $(BOARD_AVB_INIT_BOOT_KEY_PATH)
+	cp $(INTERNAL_PREBUILT_INIT_BOOT_IMAGE) $@
+	$(AVBTOOL) add_hash_footer \
+	    --image $@ \
+	    --partition_size $(BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE) \
+	    --partition_name boot $(INTERNAL_AVB_INIT_BOOT_SIGNING_ARGS) \
+	    $(BOARD_AVB_INIT_BOOT_ADD_HASH_FOOTER_ARGS)
+else
+$(INSTALLED_INIT_BOOT_IMAGE_TARGET): $(INTERNAL_PREBUILT_INIT_BOOT_IMAGE)
+	cp $(INTERNAL_PREBUILT_INIT_BOOT_IMAGE) $@
+endif # BOARD_AVB_ENABLE
+
+else # BOARD_PREBUILT_INIT_BOOT_IMAGE not defined
+INSTALLED_INIT_BOOT_IMAGE_TARGET :=
+endif # BOARD_PREBUILT_INIT_BOOT_IMAGE
+
+endif # BUILDING_INIT_BOOT_IMAGE is not true
+# -----------------------------------------------------------------
 # vendor boot image
 ifeq ($(BUILDING_VENDOR_BOOT_IMAGE),true)
 
@@ -3621,9 +3679,13 @@
     --prop com.android.build.pvmfw.fingerprint:$(BUILD_FINGERPRINT_FROM_FILE)
 
 # The following vendor- and odm-specific images needs explicit SPL set per board.
+# TODO(b/210875415) Is this security_patch property used? Should it be removed from
+# boot.img when there is no platform ramdisk included in it?
 ifdef BOOT_SECURITY_PATCH
 BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS += \
     --prop com.android.build.boot.security_patch:$(BOOT_SECURITY_PATCH)
+BOARD_AVB_INIT_BOOT_ADD_HASH_FOOTER_ARGS += \
+    --prop com.android.build.init_boot.security_patch:$(BOOT_SECURITY_PATCH)
 endif
 
 ifdef VENDOR_SECURITY_PATCH
@@ -3652,6 +3714,7 @@
 endif
 
 BOOT_FOOTER_ARGS := BOARD_AVB_BOOT_ADD_HASH_FOOTER_ARGS
+INIT_BOOT_FOOTER_ARGS := BOARD_AVB_INIT_BOOT_ADD_HASH_FOOTER_ARGS
 VENDOR_BOOT_FOOTER_ARGS := BOARD_AVB_VENDOR_BOOT_ADD_HASH_FOOTER_ARGS
 DTBO_FOOTER_ARGS := BOARD_AVB_DTBO_ADD_HASH_FOOTER_ARGS
 PVMFW_FOOTER_ARGS := BOARD_AVB_PVMFW_ADD_HASH_FOOTER_ARGS
@@ -3735,6 +3798,10 @@
 $(eval $(call check-and-set-avb-args,boot))
 endif
 
+ifdef INSTALLED_INIT_BOOT_IMAGE_TARGET
+$(eval $(call check-and-set-avb-args,init_boot))
+endif
+
 ifdef INSTALLED_VENDOR_BOOTIMAGE_TARGET
 $(eval $(call check-and-set-avb-args,vendor_boot))
 endif
@@ -3831,6 +3898,9 @@
   $(if $(BOARD_AVB_BOOT_KEY_PATH),\
     $(hide) $(AVBTOOL) extract_public_key --key $(BOARD_AVB_BOOT_KEY_PATH) \
       --output $(1)/boot.avbpubkey)
+  $(if $(BOARD_AVB_INIT_BOOT_KEY_PATH),\
+    $(hide) $(AVBTOOL) extract_public_key --key $(BOARD_AVB_INIT_BOOT_KEY_PATH) \
+      --output $(1)/init_boot.avbpubkey)
   $(if $(BOARD_AVB_VENDOR_BOOT_KEY_PATH),\
     $(AVBTOOL) extract_public_key --key $(BOARD_AVB_VENDOR_BOOT_KEY_PATH) \
       --output $(1)/vendor_boot.avbpubkey)
@@ -3934,6 +4004,7 @@
 $(INSTALLED_VBMETAIMAGE_TARGET): \
 	    $(AVBTOOL) \
 	    $(INSTALLED_BOOTIMAGE_TARGET) \
+	    $(INSTALLED_INIT_BOOT_IMAGE_TARGET) \
 	    $(INSTALLED_VENDOR_BOOTIMAGE_TARGET) \
 	    $(INSTALLED_SYSTEMIMAGE_TARGET) \
 	    $(INSTALLED_VENDORIMAGE_TARGET) \
@@ -4505,6 +4576,10 @@
 else
 	echo "boot_images=$(foreach b,$(INSTALLED_BOOTIMAGE_TARGET),$(notdir $(b)))" >> $@
 endif
+ifneq ($(INSTALLED_INIT_BOOT_IMAGE_TARGET),)
+	$(hide) echo "init_boot=true" >> $@
+	$(hide) echo "init_boot_size=$(BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE)" >> $@
+endif
 ifeq ($(BOARD_RAMDISK_USE_LZ4),true)
 	echo "lz4_ramdisks=true" >> $@
 endif
@@ -4538,6 +4613,7 @@
 	$(hide) echo 'mkbootimg_args=$(BOARD_MKBOOTIMG_ARGS)' >> $@
 	$(hide) echo 'recovery_mkbootimg_args=$(BOARD_RECOVERY_MKBOOTIMG_ARGS)' >> $@
 	$(hide) echo 'mkbootimg_version_args=$(INTERNAL_MKBOOTIMG_VERSION_ARGS)' >> $@
+	$(hide) echo 'mkbootimg_init_args=$(BOARD_MKBOOTIMG_INIT_ARGS)' >> $@
 ifdef BOARD_GKI_SIGNING_KEY_PATH
 	$(hide) echo 'gki_signing_key_path=$(BOARD_GKI_SIGNING_KEY_PATH)' >> $@
 	$(hide) echo 'gki_signing_algorithm=$(BOARD_GKI_SIGNING_ALGORITHM)' >> $@
@@ -4915,9 +4991,10 @@
   $(BUILT_TARGET_FILES_PACKAGE): $(INSTALLED_SYSTEM_EXTIMAGE_TARGET)
 endif
 
-ifdef BUILDING_BOOT_IMAGE
+ifneq (,$(BUILDING_BOOT_IMAGE)$(BUILDING_INIT_BOOT_IMAGE))
   $(BUILT_TARGET_FILES_PACKAGE): $(INTERNAL_RAMDISK_FILES)
-endif
+endif  # BUILDING_BOOT_IMAGE != "" || BUILDING_INIT_BOOT_IMAGE != ""
+
 ifneq (,$(INTERNAL_PREBUILT_BOOTIMAGE) $(filter true,$(BOARD_COPY_BOOT_IMAGE_TO_TARGET_FILES)))
   $(BUILT_TARGET_FILES_PACKAGE): $(INSTALLED_BOOTIMAGE_TARGET)
 endif
@@ -5239,6 +5316,10 @@
 	$(hide) mkdir -p $(zip_root)/IMAGES
 	$(hide) cp $(INSTALLED_SYSTEM_EXTIMAGE_TARGET) $(zip_root)/IMAGES/
 endif
+ifdef BOARD_PREBUILT_INIT_BOOT_IMAGE
+	$(hide) mkdir -p $(zip_root)/IMAGES
+	$(hide) cp $(INSTALLED_INIT_BOOT_IMAGE_TARGET) $(zip_root)/IMAGES/
+endif
 ifndef BOARD_PREBUILT_BOOTIMAGE
 ifneq (,$(INTERNAL_PREBUILT_BOOTIMAGE) $(filter true,$(BOARD_COPY_BOOT_IMAGE_TO_TARGET_FILES)))
 ifdef INSTALLED_BOOTIMAGE_TARGET
@@ -5316,6 +5397,13 @@
 	@# BOOT/RAMDISK exists and contains the ramdisk for recovery if using BOARD_USES_RECOVERY_AS_BOOT.
 	$(hide) $(call fs_config,$(zip_root)/BOOT/RAMDISK,) > $(zip_root)/META/boot_filesystem_config.txt
 endif
+ifdef BUILDING_INIT_BOOT_IMAGE
+	$(hide) $(call package_files-copy-root, $(TARGET_RAMDISK_OUT),$(zip_root)/INIT_BOOT/RAMDISK)
+	$(hide) $(call fs_config,$(zip_root)/INIT_BOOT/RAMDISK,) > $(zip_root)/META/init_boot_filesystem_config.txt
+ifdef BOARD_KERNEL_PAGESIZE
+	$(hide) echo "$(BOARD_KERNEL_PAGESIZE)" > $(zip_root)/INIT_BOOT/pagesize
+endif # BOARD_KERNEL_PAGESIZE
+endif # BUILDING_INIT_BOOT_IMAGE
 ifneq ($(INSTALLED_VENDOR_BOOTIMAGE_TARGET),)
 	$(call fs_config,$(zip_root)/VENDOR_BOOT/RAMDISK,) > $(zip_root)/META/vendor_boot_filesystem_config.txt
 endif
@@ -5629,6 +5717,7 @@
     $(INSTALLED_SYSTEMIMAGE_TARGET) \
     $(INSTALLED_RAMDISK_TARGET) \
     $(INSTALLED_BOOTIMAGE_TARGET) \
+    $(INSTALLED_INIT_BOOT_IMAGE_TARGET) \
     $(INSTALLED_USERDATAIMAGE_TARGET) \
     $(INSTALLED_VENDORIMAGE_TARGET) \
     $(INSTALLED_PRODUCTIMAGE_TARGET) \
diff --git a/core/board_config.mk b/core/board_config.mk
index 6bbb3a0..95cbe3d 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -65,6 +65,7 @@
 # File system variables
 _board_strip_readonly_list += BOARD_FLASH_BLOCK_SIZE
 _board_strip_readonly_list += BOARD_BOOTIMAGE_PARTITION_SIZE
+_board_strip_readonly_list += BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE
 _board_strip_readonly_list += BOARD_RECOVERYIMAGE_PARTITION_SIZE
 _board_strip_readonly_list += BOARD_SYSTEMIMAGE_PARTITION_SIZE
 _board_strip_readonly_list += BOARD_SYSTEMIMAGE_FILE_SYSTEM_TYPE
@@ -122,6 +123,9 @@
 _board_strip_readonly_list += BOARD_MOVE_GSI_AVB_KEYS_TO_VENDOR_BOOT
 _board_strip_readonly_list += BOARD_COPY_BOOT_IMAGE_TO_TARGET_FILES
 
+# Prebuilt image variables
+_board_strip_readonly_list += BOARD_PREBUILT_INIT_BOOT_IMAGE
+
 # Defines the list of logical vendor ramdisk names to build or include in vendor_boot.
 _board_strip_readonly_list += BOARD_VENDOR_RAMDISK_FRAGMENTS
 
@@ -461,6 +465,25 @@
 endif
 .KATI_READONLY := BUILDING_BOOT_IMAGE
 
+# Are we building an init boot image
+BUILDING_INIT_BOOT_IMAGE :=
+ifeq ($(PRODUCT_BUILD_INIT_BOOT_IMAGE),)
+  ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
+    BUILDING_INIT_BOOT_IMAGE :=
+  else ifdef BOARD_PREBUILT_INIT_BOOT_IMAGE
+    BUILDING_INIT_BOOT_IMAGE :=
+  else ifdef BOARD_INIT_BOOT_IMAGE_PARTITION_SIZE
+    BUILDING_INIT_BOOT_IMAGE := true
+  endif
+else ifeq ($(PRODUCT_BUILD_INIT_BOOT_IMAGE),true)
+  ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
+    $(error PRODUCT_BUILD_INIT_BOOT_IMAGE is true, but so is BOARD_USES_RECOVERY_AS_BOOT. Use only one option.)
+  else
+    BUILDING_INIT_BOOT_IMAGE := true
+  endif
+endif
+.KATI_READONLY := BUILDING_INIT_BOOT_IMAGE
+
 # Are we building a recovery image
 BUILDING_RECOVERY_IMAGE :=
 ifeq ($(PRODUCT_BUILD_RECOVERY_IMAGE),)
@@ -569,6 +592,11 @@
     $(warning PRODUCT_BUILD_DEBUG_BOOT_IMAGE is true, but we're not building a boot image. \
       Skip building the debug boot image.)
   endif
+else ifdef BUILDING_INIT_BOOT_IMAGE
+  ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),true)
+    $(warning PRODUCT_BUILD_DEBUG_BOOT_IMAGE is true, but we don't have a ramdisk in the boot image. \
+      Skip building the debug boot image.)
+  endif
 else
   ifeq ($(PRODUCT_BUILD_DEBUG_BOOT_IMAGE),)
     BUILDING_DEBUG_BOOT_IMAGE := true
diff --git a/core/main.mk b/core/main.mk
index f7cf8de..d17f0cb 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1603,6 +1603,9 @@
 .PHONY: bootimage
 bootimage: $(INSTALLED_BOOTIMAGE_TARGET)
 
+.PHONY: initbootimage
+bootimage: $(INSTALLED_INIT_BOOT_IMAGE_TARGET)
+
 ifeq (true,$(PRODUCT_EXPORT_BOOT_IMAGE_TO_DIST))
 $(call dist-for-goals, bootimage, $(INSTALLED_BOOTIMAGE_TARGET))
 endif
@@ -1629,6 +1632,7 @@
     $(INSTALLED_SYSTEMIMAGE_TARGET) \
     $(INSTALLED_RAMDISK_TARGET) \
     $(INSTALLED_BOOTIMAGE_TARGET) \
+    $(INSTALLED_INIT_BOOT_IMAGE_TARGET) \
     $(INSTALLED_RADIOIMAGE_TARGET) \
     $(INSTALLED_DEBUG_RAMDISK_TARGET) \
     $(INSTALLED_DEBUG_BOOTIMAGE_TARGET) \
diff --git a/core/product.mk b/core/product.mk
index 31b1beb..04c59ff 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -395,6 +395,7 @@
 _product_single_value_vars += PRODUCT_BUILD_USERDATA_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_RECOVERY_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_BOOT_IMAGE
+_product_single_value_vars += PRODUCT_BUILD_INIT_BOOT_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_DEBUG_BOOT_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_VENDOR_BOOT_IMAGE
 _product_single_value_vars += PRODUCT_BUILD_DEBUG_VENDOR_BOOT_IMAGE