diff --git a/core/Makefile b/core/Makefile
index e94939b..4959e0e 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1302,12 +1302,12 @@
 .PHONY: recoveryimage
 recoveryimage: $(INSTALLED_RECOVERYIMAGE_TARGET) $(RECOVERY_RESOURCE_ZIP)
 
-ifeq ($(BOARD_NAND_PAGE_SIZE),)
-BOARD_NAND_PAGE_SIZE := 2048
+ifneq ($(BOARD_NAND_PAGE_SIZE),)
+$(error MTD device is no longer supported and thus BOARD_NAND_PAGE_SIZE is deprecated.)
 endif
 
-ifeq ($(BOARD_NAND_SPARE_SIZE),)
-BOARD_NAND_SPARE_SIZE := 64
+ifneq ($(BOARD_NAND_SPARE_SIZE),)
+$(error MTD device is no longer supported and thus BOARD_NAND_SPARE_SIZE is deprecated.)
 endif
 
 # -----------------------------------------------------------------
diff --git a/core/definitions.mk b/core/definitions.mk
index 550634b..532d46d 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2745,39 +2745,16 @@
 $(error HOST_OS must define get-file-size)
 endif
 
-# Convert a partition data size (eg, as reported in /proc/mtd) to the
-# size of the image used to flash that partition (which includes a
-# spare area for each page).
-# $(1): the partition data size
-define image-size-from-data-size
-$(strip $(eval _isfds_value := $$(shell echo $$$$(($(1) / $(BOARD_NAND_PAGE_SIZE) * \
-  ($(BOARD_NAND_PAGE_SIZE)+$(BOARD_NAND_SPARE_SIZE))))))\
-$(if $(filter 0, $(_isfds_value)),$(shell echo $$(($(BOARD_NAND_PAGE_SIZE)+$(BOARD_NAND_SPARE_SIZE)))),$(_isfds_value))\
-$(eval _isfds_value :=))
-endef
-
 # $(1): The file(s) to check (often $@)
-# $(2): The maximum total image size, in decimal bytes.
-#    Make sure to take into account any reserved space needed for the FS.
-#
-# If $(2) is empty, evaluates to "true"
-#
-# Reserve bad blocks.  Make sure that MAX(1% of partition size, 2 blocks)
-# is left over after the image has been flashed.  Round the 1% up to the
-# next whole flash block size.
-define assert-max-file-size
+# $(2): The partition size.
+define assert-max-image-size
 $(if $(2), \
   size=$$(for i in $(1); do $(call get-file-size,$$i); echo +; done; echo 0); \
   total=$$(( $$( echo "$$size" ) )); \
   printname=$$(echo -n "$(1)" | tr " " +); \
-  img_blocksize=$(call image-size-from-data-size,$(BOARD_FLASH_BLOCK_SIZE)); \
-  twoblocks=$$((img_blocksize * 2)); \
-  onepct=$$((((($(2) / 100) - 1) / img_blocksize + 1) * img_blocksize)); \
-  reserve=$$((twoblocks > onepct ? twoblocks : onepct)); \
-  maxsize=$$(($(2) - reserve)); \
-  echo "$$printname maxsize=$$maxsize blocksize=$$img_blocksize total=$$total reserve=$$reserve"; \
+  maxsize=$(2); \
   if [ "$$total" -gt "$$maxsize" ]; then \
-    echo "error: $$printname too large ($$total > [$(2) - $$reserve])"; \
+    echo "error: $$printname too large ($$total > $$maxsize)"; \
     false; \
   elif [ "$$total" -gt $$((maxsize - 32768)) ]; then \
     echo "WARNING: $$printname approaching size limit ($$total now; limit $$maxsize)"; \
@@ -2787,17 +2764,6 @@
  )
 endef
 
-# Like assert-max-file-size, but the second argument is a partition
-# size, which we'll convert to a max image size before checking it
-# against the files.
-#
-# $(1): The file(s) to check (often $@)
-# $(2): The partition size.
-define assert-max-image-size
-$(if $(2), \
-  $(call assert-max-file-size,$(1),$(call image-size-from-data-size,$(2))))
-endef
-
 
 ###########################################################
 ## Define device-specific radio files
diff --git a/target/board/generic_arm64_a/BoardConfig.mk b/target/board/generic_arm64_a/BoardConfig.mk
index fbac417..88bd87c 100644
--- a/target/board/generic_arm64_a/BoardConfig.mk
+++ b/target/board/generic_arm64_a/BoardConfig.mk
@@ -63,8 +63,6 @@
 
 BOARD_SYSTEMIMAGE_PARTITION_SIZE := 1610612736	# 1.5 GB
 
-# TODO(b/35790399): remove when b/35790399 is fixed.
-BOARD_NAND_SPARE_SIZE := 0
 BOARD_FLASH_BLOCK_SIZE := 512
 
 BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED := true
diff --git a/target/board/generic_arm64_ab/BoardConfig.mk b/target/board/generic_arm64_ab/BoardConfig.mk
index 99dbe9f..dafd592 100644
--- a/target/board/generic_arm64_ab/BoardConfig.mk
+++ b/target/board/generic_arm64_ab/BoardConfig.mk
@@ -74,8 +74,6 @@
 # Fix this!
 BOARD_SYSTEMIMAGE_PARTITION_SIZE := 2147483648
 
-# TODO(b/35790399): remove when b/35790399 is fixed.
-BOARD_NAND_SPARE_SIZE := 0
 BOARD_FLASH_BLOCK_SIZE := 512
 
 BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED := true
diff --git a/target/board/generic_arm_a/BoardConfig.mk b/target/board/generic_arm_a/BoardConfig.mk
index 6c1b36f..6530e6e 100644
--- a/target/board/generic_arm_a/BoardConfig.mk
+++ b/target/board/generic_arm_a/BoardConfig.mk
@@ -55,8 +55,6 @@
 
 BOARD_SYSTEMIMAGE_PARTITION_SIZE := 1610612736
 
-# TODO(b/35790399): remove when b/35790399 is fixed.
-BOARD_NAND_SPARE_SIZE := 0
 BOARD_FLASH_BLOCK_SIZE := 512
 
 BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED := true