diff --git a/kernel/Makefile b/kernel/Makefile
index 041ea02..1deeeac 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -12,73 +12,71 @@
 #   d    = int | in_asm | ...	QEMU debug info
 #   mode = debug | release
 #   LOG  = off | error | warn | info | debug | trace
-#   smp                         SMP core number
+#   smp  = 1 | 2 | ...          SMP core number
 #   board = fpga				Only available on riscv32, build without bbl, run on board
 #         | raspi3				Only available on aarch64, run on Raspberry Pi 3 Model B/B+
+#   nommu						Only available on riscv32, build for M-Mode, without MMU
 
 arch ?= riscv32
 board ?= raspi3
 mode ?= debug
 LOG  ?= debug
 smp  ?= 4
+nommu ?=
 
 target := $(arch)-blog_os
 kernel := target/$(target)/$(mode)/ucore
 bin := target/$(target)/$(mode)/kernel.bin
 bootimage := target/$(target)/bootimage.bin
 
-user_bin_path := ../user/target/$(arch)-ucore/debug
-user_bins := $(patsubst $(user_bin_path)/%.d, $(user_bin_path)/%, $(wildcard $(user_bin_path)/*.d))
-user_obj := build/$(arch)/user.o
-SFSIMG := ../user/img/ucore-i386-pic.img
-
 ### qemu options ###
-ifeq ($(arch), x86_64)
 qemu_opts := \
-	-drive format=raw,file=$(bootimage) \
-	-drive format=raw,file=$(SFSIMG),media=disk,cache=writeback \
 	-smp cores=$(smp) \
-	-serial mon:stdio \
-	-device isa-debug-exit \
 	-nographic
+
+ifeq ($(arch), x86_64)
+qemu_opts += \
+	-drive format=raw,file=$(bootimage) \
+	-drive format=raw,file="../user/img/ucore-i386-pic.img",media=disk,cache=writeback \
+	-serial mon:stdio \
+	-device isa-debug-exit
+
 else ifeq ($(arch), riscv32)
-qemu_opts := \
+qemu_opts += \
 	-machine virt \
-	-kernel $(bin) \
-	-nographic \
-	-smp cores=$(smp)
+	-kernel $(bin)
 ifdef nommu
-qemu_opts := $(qemu_opts) -cpu rv32imacu-nommu
+qemu_opts += -cpu rv32imacu-nommu
 endif
+
 else ifeq ($(arch), aarch64)
-qemu_opts := \
+qemu_opts += \
 	-machine $(board) \
 	-serial null -serial mon:stdio \
-	-nographic \
-	-kernel $(bin) \
-	-smp cores=$(smp)
+	-kernel $(bin)
 endif
 
 ifdef d
-qemu_opts := $(qemu_opts) -d $(d)
+qemu_opts += -d $(d)
 endif
 
 ### build args ###
 ifeq ($(arch), riscv32)
 ifeq ($(board), fpga)
-features := $(features) no_bbl
+features += no_bbl
 endif
 endif
 
 ifdef nommu
-features := $(features) no_mmu
+features += no_mmu
+bbl_m_mode := --enable-boot-machine
 endif
 
-features := $(features) board_$(board)
+features += board_$(board)
 build_args := --target $(target).json --features "$(features)"
 
 ifeq ($(mode), release)
-build_args := $(build_args) --release
+build_args += --release
 endif
 
 
@@ -146,6 +144,7 @@ else
 	mkdir -p build && \
 	cd build && \
 	../configure \
+		$(bbl_m_mode) \
 		--with-arch=rv32imac \
 		--disable-fp-emulation \
 		--host=riscv64-unknown-elf \
@@ -167,12 +166,6 @@ else
 	@CC=$(cc) cargo xbuild $(build_args)
 endif
 
-# make user.o from binary files
-$(user_obj): $(user_bins)
-	@cd $(user_bin_path) && \
-		$(ld) -o $(abspath $@) $(patsubst %, -b binary %, $(notdir $(user_bins)))
-
-
 
 ### install ###
 ifeq ($(board), raspi3)