diff --git a/engine/src/flutter/sky/tools/roll/patch.py b/engine/src/flutter/sky/tools/roll/patch.py
index fbc2389e26..5168dac36e 100755
--- a/engine/src/flutter/sky/tools/roll/patch.py
+++ b/engine/src/flutter/sky/tools/roll/patch.py
@@ -14,6 +14,10 @@ def patch_and_filter(dest_dir, relative_patches_dir):
       lambda line: not "gyp_environment" in line)
   utils.commit("filter gyp_environment out of build/landmines.py")
 
+  utils.filter_file("mojo/dart/embedder/BUILD.gn",
+      lambda line: not "tonic" in line)
+  utils.commit("filter tonic out of mojo/dart/embedder/BUILD.gn")
+
   patch(dest_dir, relative_patches_dir)
 
 
diff --git a/engine/src/flutter/sky/tools/roll/roll.py b/engine/src/flutter/sky/tools/roll/roll.py
index cd3cb78bb5..4eea4a2887 100755
--- a/engine/src/flutter/sky/tools/roll/roll.py
+++ b/engine/src/flutter/sky/tools/roll/roll.py
@@ -136,23 +136,23 @@ def main():
 
   args = parser.parse_args()
 
+  dest_dir = os.path.abspath(args.dest_dir)
+
   if args.mojo_dir:
-      rev(args.mojo_dir, args.dest_dir, dirs_from_mojo, 'mojo')
+      rev(os.path.abspath(args.mojo_dir), dest_dir, dirs_from_mojo, 'mojo')
 
       try:
-          patch.patch_and_filter(args.dest_dir,
-                                 os.path.join('patches', 'mojo'))
+          patch.patch_and_filter(dest_dir, os.path.join('patches', 'mojo'))
       except subprocess.CalledProcessError:
           print "ERROR: Roll failed due to a patch not applying"
           print "Fix the patch to apply, commit the result, and re-run this script"
           return 1
 
   if args.chromium_dir:
-      rev(args.chromium_dir, args.dest_dir, dirs_from_chromium, 'chromium')
+      rev(os.path.abspath(args.chromium_dir), dest_dir, dirs_from_chromium, 'chromium')
 
       try:
-          patch.patch_and_filter(args.dest_dir,
-                                 os.path.join('patches', 'chromium'))
+          patch.patch_and_filter(dest_dir, os.path.join('patches', 'chromium'))
       except subprocess.CalledProcessError:
           print "ERROR: Roll failed due to a patch not applying"
           print "Fix the patch to apply, commit the result, and re-run this script"