diff --git a/litex/build/xilinx/ise.py b/litex/build/xilinx/ise.py
old mode 100644
new mode 100755
index 5c6b01190..1abed5b0b
--- a/litex/build/xilinx/ise.py
+++ b/litex/build/xilinx/ise.py
@@ -96,8 +96,8 @@ def _run_yosys(device, sources, vincpaths, build_name):
     else:
         raise OSError("Unsupported device")
 
-    ys_contents += """hierarchy -top top
-synth_xilinx -top top -family {family} -ise
+    ys_contents += """hierarchy -top {build_name}
+synth_xilinx -top {build_name} -family {family} -ise
 write_edif -pvector bra {build_name}.edif""".format(build_name=build_name, family=family)
 
     ys_name = build_name + ".ys"