diff --git a/target/linux/ramips/image/mt7620.mk b/target/linux/ramips/image/mt7620.mk
index 8e742a935d..9ccd3d9833 100644
--- a/target/linux/ramips/image/mt7620.mk
+++ b/target/linux/ramips/image/mt7620.mk
@@ -66,6 +66,7 @@ TARGET_DEVICES += ArcherC50
 
 define Device/ex2700
   DTS := EX2700
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   IMAGES += factory.bin
   KERNEL := $(KERNEL_DTB) | uImage lzma | pad-kernel-ex2700
@@ -76,6 +77,7 @@ TARGET_DEVICES += ex2700
 
 define Device/wt3020-4M
   DTS := WT3020-4M
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   IMAGES += factory.bin
   IMAGE/factory.bin := $$(IMAGE/sysupgrade.bin) | poray-header -B WT3020 -F 4M
@@ -394,14 +396,16 @@ TARGET_DEVICES += tiny-ac
 
 define Device/dch-m225
   DTS := DCH-M225
+  BLOCKSIZE := 4k
   IMAGES += factory.bin
   IMAGE_SIZE := 6848k
   IMAGE/sysupgrade.bin := \
-	append-kernel | pad-offset 65536 64 | append-rootfs | \
+	append-kernel | pad-offset $$$$(BLOCKSIZE) 64 | append-rootfs | \
 	seama -m "dev=/dev/mtdblock/2" -m "type=firmware" | \
 	pad-rootfs | check-size $$$$(IMAGE_SIZE)
   IMAGE/factory.bin := \
-	append-kernel | pad-offset 65536 64 | append-rootfs | pad-rootfs -x 64 | \
+	append-kernel | pad-offset $$$$(BLOCKSIZE) 64 | \
+	append-rootfs | pad-rootfs -x 64 | \
 	seama -m "dev=/dev/mtdblock/2" -m "type=firmware" | \
 	seama-seal -m "signature=wapn22_dlink.2013gui_dap1320b" | \
 	check-size $$$$(IMAGE_SIZE)
diff --git a/target/linux/ramips/image/mt7621.mk b/target/linux/ramips/image/mt7621.mk
index 750e7e1e4b..47778c4636 100644
--- a/target/linux/ramips/image/mt7621.mk
+++ b/target/linux/ramips/image/mt7621.mk
@@ -37,6 +37,7 @@ endef
 
 define Device/mt7621
   DTS := MT7621
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := MediaTek MT7621 EVB
 endef
@@ -65,15 +66,17 @@ TARGET_DEVICES += wsr-1166
 
 define Device/dir-860l-b1
   DTS := DIR-860L-B1
+  BLOCKSIZE := 4k
   IMAGES += factory.bin
   KERNEL := kernel-bin | patch-dtb | relocate-kernel | lzma | uImage lzma
   IMAGE_SIZE := $(ralink_default_fw_size_16M)
   IMAGE/sysupgrade.bin := \
-	append-kernel | pad-offset 65536 64 | append-rootfs | \
+	append-kernel | pad-offset $$$$(BLOCKSIZE) 64 | append-rootfs | \
 	seama -m "dev=/dev/mtdblock/2" -m "type=firmware" | \
 	pad-rootfs | check-size $$$$(IMAGE_SIZE)
   IMAGE/factory.bin := \
-	append-kernel | pad-offset 65536 64 | append-rootfs | pad-rootfs -x 64 | \
+	append-kernel | pad-offset $$$$(BLOCKSIZE) 64 | \
+	append-rootfs | pad-rootfs -x 64 | \
 	seama -m "dev=/dev/mtdblock/2" -m "type=firmware" | \
 	seama-seal -m "signature=wrgac13_dlink.2013gui_dir860lb" | \
 	check-size $$$$(IMAGE_SIZE)
diff --git a/target/linux/ramips/image/mt7628.mk b/target/linux/ramips/image/mt7628.mk
index bd7d5bf7a4..2a130b5d24 100644
--- a/target/linux/ramips/image/mt7628.mk
+++ b/target/linux/ramips/image/mt7628.mk
@@ -4,6 +4,7 @@
 
 define Device/mt7628
   DTS := MT7628
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := MediaTek MT7628 EVB
   DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci kmod-ledtrig-usbdev
diff --git a/target/linux/ramips/image/rt288x.mk b/target/linux/ramips/image/rt288x.mk
index ebb523e461..7e7652e9ec 100644
--- a/target/linux/ramips/image/rt288x.mk
+++ b/target/linux/ramips/image/rt288x.mk
@@ -15,6 +15,7 @@ endef
 
 define Device/ar670w
   DTS := AR670W
+  BLOCKSIZE := 64k
   DEVICE_TITLE := Airlink AR670W
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   KERNEL := $(KERNEL_DTB)
@@ -41,6 +42,7 @@ TARGET_DEVICES += f5d8235v1
 
 define Device/rt-n15
   DTS := RT-N15
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Asus RT-N15
   DEVICE_PACKAGES := kmod-switch-rtl8366s
@@ -49,6 +51,7 @@ TARGET_DEVICES += rt-n15
 
 define Device/v11st-fe
   DTS := V11STFE
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Ralink V11ST-FE
 endef
@@ -56,6 +59,7 @@ TARGET_DEVICES += v11st-fe
 
 define Device/wli-tx4-ag300n
   DTS := WLI-TX4-AG300N
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Buffalo WLI-TX4-AG300N
 endef
@@ -63,6 +67,7 @@ TARGET_DEVICES += wli-tx4-ag300n
 
 define Device/wzr-agl300nh
   DTS := WZR-AGL300NH
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Buffalo WZR-AGL300NH
   DEVICE_PACKAGES := kmod-switch-rtl8366s
diff --git a/target/linux/ramips/image/rt305x.mk b/target/linux/ramips/image/rt305x.mk
index ede2728a32..13193ae796 100644
--- a/target/linux/ramips/image/rt305x.mk
+++ b/target/linux/ramips/image/rt305x.mk
@@ -107,6 +107,7 @@ TARGET_DEVICES += f7c027
 
 define Device/air3gii
   DTS := AIR3GII
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := AirLive Air3GII
 endef
@@ -122,6 +123,7 @@ TARGET_DEVICES += awm003-evb
 
 define Device/awmapn2403
   DTS := AWAPN2403
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := AsiaRF AWAPN2403
 endef
@@ -145,6 +147,7 @@ TARGET_DEVICES += carambola
 
 define Device/d105
   DTS := D105
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Huawei D105
 endef
@@ -167,6 +170,7 @@ TARGET_DEVICES += dir-620-d1
 
 define Device/esr-9753
   DTS := ESR-9753
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := EnGenius ESR-9753
 endef
@@ -221,6 +225,7 @@ TARGET_DEVICES += mofi3500-3gn
 
 define Device/3g150b
   DTS := 3G150B
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   UIMAGE_NAME:= Linux Kernel Image
   DEVICE_TITLE := Tenda 3G150B
@@ -238,6 +243,7 @@ TARGET_DEVICES += mr-102n
 
 define Device/mpr-a1
   DTS := MPRA1
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   UIMAGE_NAME:= Linux Kernel Image
   DEVICE_TITLE := HAME MPR-A1
@@ -257,6 +263,7 @@ TARGET_DEVICES += mpr-a2
 
 define Device/dir-300-b7
   DTS := DIR-300-B7
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := D-Link DIR-300 B7
 endef
@@ -272,6 +279,7 @@ TARGET_DEVICES += dir-320-b1
 
 define Device/nbg-419n
   DTS := NBG-419N
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := ZyXEL NBG-419N
 endef
@@ -321,6 +329,7 @@ TARGET_DEVICES += miniembwifi
 
 define Device/psr-680w
   DTS := PSR-680W
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Petatel PSR-680W Wireless 3G Router
 endef
@@ -357,6 +366,7 @@ TARGET_DEVICES += rt5350f-olinuxino-evb
 
 define Device/rt-g32-b1
   DTS := RT-G32-B1
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Asus RT-G32 B1
 endef
@@ -365,6 +375,7 @@ TARGET_DEVICES += rt-g32-b1
 
 define Device/rt-n10-plus
   DTS := RT-N10-PLUS
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Asus RT-N10+
 endef
@@ -380,19 +391,23 @@ TARGET_DEVICES += rut5xx
 
 define Device/sl-r7205
   DTS := SL-R7205
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Skyline SL-R7205 Wireless 3G Router
 endef
 TARGET_DEVICES += sl-r7205
 
+
 define Device/tew-714tru
   DTS := TEW-714TRU
   DEVICE_TITLE := TRENDnet TEW-714TRU
 endef
 TARGET_DEVICES += tew-714tru
 
+
 define Device/v22rw-2x2
   DTS := V22RW-2X2
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Ralink AP-RT3052-V22RW-2X2
 endef
@@ -408,6 +423,7 @@ TARGET_DEVICES += w502u
 
 define Device/wcr150gn
   DTS := WCR150GN
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Sparklan WCR-150GN
 endef
@@ -416,6 +432,7 @@ TARGET_DEVICES += wcr150gn
 
 define Device/mzk-dp150n
   DTS := MZK-DP150N
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Planex MZK-DP150N
   DEVICE_PACKAGES := kmod-spi-dev
@@ -441,6 +458,7 @@ TARGET_DEVICES += wizfi630a
 
 define Device/wl-330n
   DTS := WL-330N
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Asus WL-330N
 endef
@@ -449,6 +467,7 @@ TARGET_DEVICES += wl-330n
 
 define Device/wl-330n3g
   DTS := WL-330N3G
+  BLOCKSIZE := 4k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Asus WL-330N3G
   DEVICE_PACKAGES :=
@@ -458,6 +477,7 @@ TARGET_DEVICES += wl-330n3g
 
 define Device/wl-351
   DTS := WL-351
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := Sitecom WL-351 v1
   DEVICE_PACKAGES := kmod-switch-rtl8366rb kmod-swconfig swconfig
@@ -467,6 +487,7 @@ TARGET_DEVICES += wl-351
 
 define Device/ur-326n4g
   DTS := UR-326N4G
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := UPVEL UR-326N4G
   DEVICE_PACKAGES := kmod-usb-core kmod-usb-dwc2 kmod-ledtrig-usbdev
@@ -491,6 +512,7 @@ TARGET_DEVICES += wr6202
 
 define Device/xdxrn502j
   DTS := XDXRN502J
+  BLOCKSIZE := 64k
   IMAGE_SIZE := $(ralink_default_fw_size_4M)
   DEVICE_TITLE := XDX RN502J
 endef