--- ubiquity.orig/scripts/install.py	2010-03-26 10:25:10.000000000 +0100
+++ ubiquity/scripts/install.py		2010-03-26 11:08:48.000000000 +0100
@@ -667,9 +667,14 @@
         self.db.progress('INFO', 'ubiquity/install/copying')
 
         fs_size = os.path.join(self.casper_path, 'filesystem.size')
-        assert os.path.exists(fs_size), "Missing filesystem.size."
-        with open(fs_size) as total_size_fp:
-            total_size = int(total_size_fp.readline())
+        if os.path.exists(fs_size):
+            assert os.path.exists(fs_size), "Missing filesystem.size."
+            with open(fs_size) as total_size_fp:
+                total_size = int(total_size_fp.readline())
+        else:
+            cmd_getfilesystem = 'du -bs $(cat /proc/mounts | grep squashfs | cut -d " " -f2) | cut -d "/" -f1'
+            total_size = int(commands.getoutput(cmd_getfilesystem))
+            
 
         # Progress bar handling:
         # We sample progress every half-second (assuming time.time() gives