1 files changed, 8 insertions, 5 deletions
diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py
index f3240ba8d8..1f1aacc522 100644
--- a/scripts/lib/wic/filemap.py
+++ b/scripts/lib/wic/filemap.py
@@ -530,22 +530,25 @@ def filemap(image, log=None):
     except ErrorNotSupp:
         return FilemapSeek(image, log)
 
-def sparse_copy(src_fname, dst_fname, offset=0, skip=0):
+def sparse_copy(src_fname, dst_fname, offset=0, skip=0, api=None):
     """Efficiently copy sparse file to or into another file."""
-    fmap = filemap(src_fname)
+    if not api:
+        api = filemap
+    fmap = api(src_fname)
     try:
         dst_file = open(dst_fname, 'r+b')
     except IOError:
         dst_file = open(dst_fname, 'wb')
+        dst_file.truncate(os.path.getsize(src_fname))
 
     for first, last in fmap.get_mapped_ranges(0, fmap.blocks_cnt):
         start = first * fmap.block_size
         end = (last + 1) * fmap.block_size
 
         if start < skip < end:
-            start = skip
-
-        fmap._f_image.seek(start, os.SEEK_SET)
+            fmap._f_image.seek(skip, os.SEEK_SET)
+        else:
+            fmap._f_image.seek(start, os.SEEK_SET)
         dst_file.seek(offset + start, os.SEEK_SET)
 
         chunk_size = 1024 * 1024