diff --git a/target/linux/ramips/image/mt7620.mk b/target/linux/ramips/image/mt7620.mk
index f03c803b18..3f81d77832 100644
--- a/target/linux/ramips/image/mt7620.mk
+++ b/target/linux/ramips/image/mt7620.mk
@@ -65,7 +65,8 @@ define Device/ex2700
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   IMAGES += factory.bin
   KERNEL := $(KERNEL_DTB) | uImage lzma | pad-kernel-ex2700
-  IMAGE/factory.bin := $$(sysupgrade_bin) | netgear-header -B EX2700 -H 29764623+4+0+32+2x2+0
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	netgear-header -B EX2700 -H 29764623+4+0+32+2x2+0
   DEVICE_TITLE := Netgear EX2700
 endef
 TARGET_DEVICES += ex2700
@@ -76,7 +77,8 @@ define Device/wt3020-4M
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   IMAGES += factory.bin
   SUPPORTED_DEVICES := wt3020
-  IMAGE/factory.bin := $$(sysupgrade_bin) | poray-header -B WT3020 -F 4M
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	poray-header -B WT3020 -F 4M
   DEVICE_TITLE := Nexx WT3020 (4MB)
 endef
 TARGET_DEVICES += wt3020-4M
@@ -85,7 +87,8 @@ define Device/wt3020-8M
   DTS := WT3020-8M
   IMAGES += factory.bin
   SUPPORTED_DEVICES := wt3020
-  IMAGE/factory.bin := $$(sysupgrade_bin) | poray-header -B WT3020 -F 8M
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	poray-header -B WT3020 -F 8M
   DEVICE_TITLE := Nexx WT3020 (8MB)
 endef
 TARGET_DEVICES += wt3020-8M
@@ -94,7 +97,8 @@ define Device/wrh-300cr
   DTS := WRH-300CR
   IMAGE_SIZE := $(ralink_default_fw_size_16M)
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | elecom-header
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	elecom-header
   DEVICE_TITLE := Elecom WRH-300CR 
   DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci
 endef
@@ -103,7 +107,8 @@ TARGET_DEVICES += wrh-300cr
 define Device/e1700
   DTS := E1700
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | umedia-header 0x013326
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	umedia-header 0x013326
   DEVICE_TITLE := Linksys E1700
 endef
 TARGET_DEVICES += e1700
@@ -431,6 +436,7 @@ define Device/kng_rc
   DEVICE_TITLE := ZyXEL Keenetic Viva
   DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci kmod-usb-ledtrig-usbport kmod-switch-rtl8366-smi kmod-switch-rtl8367b
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(IMAGE/sysupgrade.bin) | zyimage -d 8997 -v "ZyXEL Keenetic Viva"
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	zyimage -d 8997 -v "ZyXEL Keenetic Viva"
 endef
 TARGET_DEVICES += kng_rc
diff --git a/target/linux/ramips/image/rt288x.mk b/target/linux/ramips/image/rt288x.mk
index ab56fcc44f..40bf6f1f2f 100644
--- a/target/linux/ramips/image/rt288x.mk
+++ b/target/linux/ramips/image/rt288x.mk
@@ -22,7 +22,8 @@ define Device/ar725w
   DTS := AR725W
   DEVICE_TITLE := Gemtek AR725W
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | gemtek-header ar725w
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	gemtek-header ar725w
 endef
 TARGET_DEVICES += ar725w
 
diff --git a/target/linux/ramips/image/rt3883.mk b/target/linux/ramips/image/rt3883.mk
index 5fe4a71328..abece505d7 100644
--- a/target/linux/ramips/image/rt3883.mk
+++ b/target/linux/ramips/image/rt3883.mk
@@ -7,7 +7,8 @@ define Device/br-6475nd
   BLOCKSIZE := 64k
   IMAGE_SIZE := 7744k
   IMAGE/sysupgrade.bin := append-kernel | append-rootfs | \
-	edimax-header -s CSYS -m RN54 -f 0x70000 -S 0x01100000 | pad-rootfs | append-metadata
+	edimax-header -s CSYS -m RN54 -f 0x70000 -S 0x01100000 | pad-rootfs | \
+	append-metadata | check-size $$$$(IMAGE_SIZE)
   DEVICE_TITLE := Edimax BR-6475nD
   DEVICE_PACKAGES := swconfig
 endef
@@ -69,7 +70,8 @@ define Device/tew-691gr
   DTS := TEW-691GR
   BLOCKSIZE := 64k
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | umedia-header 0x026910
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	umedia-header 0x026910
   DEVICE_TITLE := TRENDnet TEW-691GR
   DEVICE_PACKAGES := swconfig
 endef
@@ -80,7 +82,8 @@ define Device/tew-692gr
   DTS := TEW-692GR
   BLOCKSIZE := 64k
   IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | umedia-header 0x026920
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	umedia-header 0x026920
   DEVICE_TITLE := TRENDnet TEW-692GR
   DEVICE_PACKAGES := swconfig
 endef
@@ -92,27 +95,9 @@ define Device/wlr-6000
   BLOCKSIZE := 4k
   IMAGE_SIZE := 7244k
   IMAGES += factory.dlf
-  IMAGE/factory.dlf := \
-	$$(sysupgrade_bin) | senao-header -r 0x0202 -p 0x41 -t 2
+  IMAGE/factory.dlf := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
+	senao-header -r 0x0202 -p 0x41 -t 2
   DEVICE_TITLE := Sitecom WLR-6000
   DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 swconfig
 endef
 TARGET_DEVICES += wlr-6000
-
-
-define BuildFirmware/RTN56U/squashfs
-	$(call BuildFirmware/Default8M/$(1),$(1),rt-n56u,RT-N56U)
-	-mkrtn56uimg -s $(call sysupname,$(1),rt-n56u)
-	-cp $(call sysupname,$(1),rt-n56u) $(call imgname,$(1),rt-n56u)-factory.bin
-	-mkrtn56uimg -f $(call imgname,$(1),rt-n56u)-factory.bin
-endef
-
-Image/Build/Profile/RTN56U=$(call BuildFirmware/RTN56U/$(1),$(1),rt-n56u,RT-N56U)
-
-
-define LegacyDevice/RTN56U
-  BLOCKSIZE := 64k
-  DEVICE_TITLE := Asus RT-N56U
-  DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 swconfig
-endef
-LEGACY_DEVICES += RTN56U