diff --git a/Makefile b/Makefile
index 641c3ce..a11cafb 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,8 @@ grub_cfg := $(boot_src)/grub.cfg
 assembly_source_files := $(wildcard $(boot_src)/*.asm)
 assembly_object_files := $(patsubst $(boot_src)/%.asm, \
 	build/arch/$(arch)/boot/%.o, $(assembly_source_files))
-user_object_files := $(wildcard user/*.o)
+user_image_files := $(wildcard user/*.img)
+user_object_files := $(patsubst user/%.img, build/user/%.o, $(user_image_files))
 qemu_opts := -cdrom $(iso) -smp 4 -serial mon:stdio
 features := use_apic
 
@@ -95,6 +96,11 @@ build/arch/$(arch)/boot/%.o: $(boot_src)/%.asm
 	@mkdir -p $(shell dirname $@)
 	@nasm -felf64 $< -o $@
 
+# make .o from .img file
+build/user/%.o: user/%.img
+	@mkdir -p $(shell dirname $@)
+	@$(ld) -r -b binary $< -o $@
+
 # used by docker_* targets
 docker_image ?= blog_os
 tag ?= 0.1
diff --git a/src/fs.rs b/src/fs.rs
index 8081805..92ec3c2 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -3,10 +3,10 @@ use alloc::boxed::Box;
 use process;
 
 extern {
-    fn _binary_user_sfs_img_start();
-    fn _binary_user_sfs_img_end();
-    fn _binary_user_forktest_start();
-    fn _binary_user_forktest_end();
+    fn _binary_user_ucore32_img_start();
+    fn _binary_user_ucore32_img_end();
+    fn _binary_user_xv6_64_img_start();
+    fn _binary_user_xv6_64_img_end();
 }
 
 struct MemBuf(&'static [u8]);
@@ -31,7 +31,7 @@ impl Device for MemBuf {
 }
 
 pub fn load_sfs() {
-    let slice = unsafe { MemBuf::new(_binary_user_sfs_img_start, _binary_user_sfs_img_end) };
+    let slice = unsafe { MemBuf::new(_binary_user_ucore32_img_start, _binary_user_ucore32_img_end) };
     let sfs = SimpleFileSystem::open(Box::new(slice)).unwrap();
     let root = sfs.root_inode();
     let files = root.borrow().list().unwrap();
@@ -45,7 +45,5 @@ pub fn load_sfs() {
         process::add_user_process(name, unsafe { &BUF[..len] });
     }
 
-//    process::add_user_process("forktest", unsafe { MemBuf::new(_binary_user_forktest_start, _binary_user_forktest_end).0 });
-
     process::print();
 }
\ No newline at end of file
diff --git a/user/forktest.o b/user/forktest.o
deleted file mode 100755
index 13d05d5..0000000
Binary files a/user/forktest.o and /dev/null differ
diff --git a/user/ucore32.img b/user/ucore32.img
new file mode 100644
index 0000000..88949ab
Binary files /dev/null and b/user/ucore32.img differ
diff --git a/user/xv6_64.img b/user/xv6_64.img
new file mode 100644
index 0000000..94090c8
Binary files /dev/null and b/user/xv6_64.img differ