diff --git a/libsparse/Android.mk b/libsparse/Android.mk
index 9025cc0..a21e090 100644
--- a/libsparse/Android.mk
+++ b/libsparse/Android.mk
@@ -82,8 +82,8 @@
 
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := simg2simg.c
-LOCAL_MODULE := simg2simg
+LOCAL_SRC_FILES := append2simg.c
+LOCAL_MODULE := append2simg
 LOCAL_STATIC_LIBRARIES := \
     libsparse_host \
     libz
diff --git a/libsparse/append2simg.c b/libsparse/append2simg.c
new file mode 100644
index 0000000..180584f
--- /dev/null
+++ b/libsparse/append2simg.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+#include "sparse_file.h"
+#include "backed_block.h"
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#endif
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#define off64_t off_t
+#endif
+
+void usage()
+{
+    fprintf(stderr, "Usage: append2simg <output> <input>\n");
+}
+
+int main(int argc, char *argv[])
+{
+    int output;
+    int output_block;
+    char *output_path;
+    struct sparse_file *sparse_output;
+
+    int input;
+    char *input_path;
+    off64_t input_len;
+
+    if (argc == 3) {
+        output_path = argv[1];
+        input_path = argv[2];
+    } else {
+        usage();
+        exit(-1);
+    }
+
+    output = open(output_path, O_RDWR | O_BINARY);
+    if (output < 0) {
+        fprintf(stderr, "Couldn't open output file (%s)\n", strerror(errno));
+        exit(-1);
+    }
+
+    sparse_output = sparse_file_import_auto(output, true);
+    if (!sparse_output) {
+        fprintf(stderr, "Couldn't import output file\n");
+        exit(-1);
+    }
+
+    input = open(input_path, O_RDONLY | O_BINARY);
+    if (input < 0) {
+        fprintf(stderr, "Couldn't open input file (%s)\n", strerror(errno));
+        exit(-1);
+    }
+
+    input_len = lseek64(input, 0, SEEK_END);
+    if (input_len < 0) {
+        fprintf(stderr, "Couldn't get input file length (%s)\n", strerror(errno));
+        exit(-1);
+    } else if (input_len % sparse_output->block_size) {
+        fprintf(stderr, "Input file is not a multiple of the output file's block size");
+        exit(-1);
+    }
+    lseek64(input, 0, SEEK_SET);
+
+    output_block = sparse_output->len / sparse_output->block_size;
+    if (sparse_file_add_fd(sparse_output, input, 0, input_len, output_block) < 0) {
+        fprintf(stderr, "Couldn't add input file\n");
+        exit(-1);
+    }
+    sparse_output->len += input_len;
+
+    lseek64(output, 0, SEEK_SET);
+    if (sparse_file_write(sparse_output, output, false, true, false) < 0) {
+        fprintf(stderr, "Failed to write sparse file\n");
+        exit(-1);
+    }
+
+    sparse_file_destroy(sparse_output);
+    close(output);
+    close(input);
+    exit(0);
+}