1. Create folder for Zephyr OS
	mkdir zephyr_150
	cd zephyr_150

2. Clone repository (see https://www.zephyrproject.org/downloads)
	git clone https://gerrit.zephyrproject.org/r/zephyr
	cd zephyr
	git checkout tags/v1.5.0

3. Set environment variable:
	export ZEPHYR_BASE=<your_path>/zephyr_150/zephyr

4. Copy *.diff patch to $(ZEPHYR_BASE) and apply it:
	cp ../../riscv_vhdl/zephyr/v1.5.0-branch.diff .
	git apply v1.5.0-branch.diff

5. Build 'shell' example and generate ROM-image for FPGA or Simulator (GCC must be installed):
	cd samples/shell
	make ARCH=riscv64 CROSS_COMPILE=/home/<gcc_dir>/gnu-toolchain-rv64d/bin/riscv64-unknown-elf- BOARD=riscv_gnss 2>&1 | tee _err.log
	elf2raw64 outdir/zephyr.elf -h -f 262144 -l 8 -o fwimage.hex

6. Copy fwimage.hex into <git_rep>/riscv_vhdl/rocket_soc/fw_images

Your board is now udpated with the new firmware!


INFO:
Archives with patched Zephyr OS and others *.diff files are available here:
	http://gnss-sensor.com/index.php?LinkID=15
