OpenWRT Image Builder Raspberry Pi 4 Makefile

Makefile

VERSION=21.02.1
TARGET=bcm27xx-bcm2711
PROFILE=rpi-4
PACKAGES=kmod-usb-net-rtl8152 luci luci-ssl
FILESYSTEM=ext4

###################

BUILDER_BASEURL=https://downloads.openwrt.org/releases/$(VERSION)/targets/$(subst -,/,$(TARGET))
BUILDER_TARBALL=openwrt-imagebuilder-$(VERSION)-$(TARGET).Linux-x86_64.tar.xz
BUILDER=$(basename $(basename $(BUILDER_TARBALL)))

IMAGE=openwrt-$(VERSION)-$(TARGET)-$(PROFILE)-$(FILESYSTEM)-factory.img.gz
IMAGE_PATH=bin/targets/$(subst -,/,$(TARGET))/$(IMAGE)

.PHONY: all clean

all: bin/$(IMAGE)

clean:
	@rm -rf ext/ bin/

ext bin:
	@mkdir -p $@

ext/$(BUILDER_TARBALL): | ext
	@curl $(BUILDER_BASEURL)/$(BUILDER_TARBALL) -o $@

ext/$(BUILDER): | ext/$(BUILDER_TARBALL)
	@tar -C ext/ -Jxf $|

bin/$(IMAGE): ext/$(BUILDER)/$(IMAGE_PATH) | bin
	@cp $< $@

ext/$(BUILDER)/$(IMAGE_PATH): | ext/$(BUILDER)
	@make -C $| image PACKAGES="$(PACKAGES)" PROFILE="$(PROFILE)"