ramips: use dd bs=4096k instead of bs=4M to make it more portable

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 38806

target/linux/ramips/image/Makefile

@@ -368,7 +368,7 @@ define BuildFirmware/DCS930/squashfs
 	else \
 		dd if=$(KDIR)/image.$(2) of=$(KDIR)/dcs.tmp bs=64K count=5 conv=sync ;\
 		cat $(KDIR)/image.$(2) >> $(KDIR)/dcs.tmp ; \
-		dd if=$(KDIR)/dcs.tmp of=$(call imgname,$(1),$(2))-factory.bin bs=4M count=1 conv=sync ;\
+		dd if=$(KDIR)/dcs.tmp of=$(call imgname,$(1),$(2))-factory.bin bs=4096k count=1 conv=sync ;\
 		$(STAGING_DIR_HOST)/bin/mkdcs932 $(call imgname,$(1),$(2))-factory.bin ; \
 	fi
 endef