diff --git a/kernel/Cargo.toml b/kernel/Cargo.toml
index 0ac82c23..de98c1ca 100644
--- a/kernel/Cargo.toml
+++ b/kernel/Cargo.toml
@@ -97,7 +97,7 @@ minimum-image-size = 0      # The minimum output file size (in MiB)
 # (the "{}" will be replaced with the path to the bootable disk image)
 run-command = ["qemu-system-x86_64",
     "-drive", "format=raw,file={}",
-    # TODO: use SFSIMG environment variable
+    # TODO: use USER_IMG environment variable
     "-drive", "format=raw,file=../user/img/ucore-i386-pic.img,media=disk,cache=writeback",
     "-serial", "mon:stdio",
     "-device", "isa-debug-exit",
diff --git a/kernel/Makefile b/kernel/Makefile
index 516a0844..0ce9b8b9 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -19,7 +19,7 @@
 #   d    = int | in_asm | ...   QEMU debug info
 #   mode = debug | release
 #   LOG  = off | error | warn | info | debug | trace
-#   SFSIMG = <sfsimg>            SFS image path of user programs
+#   USER_IMG = <sfsimg>          image path of user programs
 #   smp     = 1 | 2 | ...        SMP core number
 #   graphic = on | off | console Enable/disable qemu graphical output, or print console to graphic output
 #   board   = none               Running on QEMU
@@ -56,18 +56,8 @@ user_dir := ../user
 
 ### export environments ###
 
-ifeq ($(arch), $(filter $(arch), aarch64 mipsel))
-#link user img, so use original image
-export SFSIMG = $(user_dir)/build/$(arch).img
-else
-# board is pc or qemu?
-ifeq ($(board), $(filter $(board), pc u540 k210 rocket_chip))
-#link user img, so use original image
-export SFSIMG = $(user_dir)/build/$(arch).img
-else
-export SFSIMG = $(user_dir)/build/$(arch).qcow2
-endif # pc or qemu
-endif # aarch64 mipsel
+export USER_IMG = $(user_dir)/build/$(arch).img
+export USER_QCOW2 = $(user_dir)/build/$(arch).qcow2
 
 ifeq ($(arch), aarch64)
 board := raspi3
@@ -107,7 +97,7 @@ qemu_opts += \
 	-device isa-debug-exit
 ifeq ($(board), none)
 qemu_opts += \
-	-drive format=qcow2,file=$(SFSIMG),media=disk,cache=writeback,id=sfsimg,if=none \
+	-drive format=qcow2,file=$(USER_QCOW2),media=disk,cache=writeback,id=sfsimg,if=none \
 	-device ahci,id=ahci0 \
 	-device ide-drive,drive=sfsimg,bus=ahci0.0
 endif
@@ -135,7 +125,7 @@ qemu_opts += \
 	-serial mon:stdio \
 	-kernel ../tools/opensbi/virt_rv32.elf \
 	-device loader,addr=0x80400000,file=$(kernel_img) \
-	-drive file=$(SFSIMG),format=qcow2,id=sfs \
+	-drive file=$(USER_QCOW2),format=qcow2,id=sfs \
 	-device virtio-blk-device,drive=sfs
 qemu_net_opts += \
 	-netdev type=tap,id=net0,script=no,downscript=no \
@@ -157,7 +147,7 @@ qemu_opts += \
 	-serial mon:stdio \
 	-kernel ../tools/opensbi/virt_rv64.elf \
 	-device loader,addr=0x80200000,file=$(kernel_img) \
-	-drive file=$(SFSIMG),format=qcow2,id=sfs \
+	-drive file=$(USER_QCOW2),format=qcow2,id=sfs \
 	-device virtio-blk-device,drive=sfs
 endif
 qemu_net_opts += \
@@ -172,7 +162,7 @@ qemu_opts += \
 	-machine $(board) \
 	-serial null -serial mon:stdio \
 	-kernel $(kernel_img) \
-	-sd $(kernel_img)
+	-drive file=$(USER_QCOW2),format=qcow2,id=sfs
 
 else ifeq ($(arch), mipsel)
 ifeq ($(board), malta)
diff --git a/kernel/build.rs b/kernel/build.rs
index 286606b9..bd4c07e6 100644
--- a/kernel/build.rs
+++ b/kernel/build.rs
@@ -7,7 +7,7 @@ use std::path::Path;
 fn main() {
     println!("cargo:rerun-if-env-changed=LOG");
     println!("cargo:rerun-if-env-changed=BOARD");
-    println!("cargo:rerun-if-env-changed=SFSIMG");
+    println!("cargo:rerun-if-env-changed=USER_IMG");
 
     let arch: String = std::env::var("ARCH").unwrap();
     let board: String = std::env::var("BOARD").unwrap();
diff --git a/kernel/src/fs/mod.rs b/kernel/src/fs/mod.rs
index 99fe306b..a90d0b7e 100644
--- a/kernel/src/fs/mod.rs
+++ b/kernel/src/fs/mod.rs
@@ -31,7 +31,7 @@ global_asm!(concat!(
 	.global _user_img_end
 _user_img_start:
     .incbin ""#,
-    env!("SFSIMG"),
+    env!("USER_IMG"),
     r#""
 _user_img_end:
 "#