diff --git a/artiq/gateware/targets/sayma_rtm.py b/artiq/gateware/targets/sayma_rtm.py
index 256637c4e..df9206dc5 100755
--- a/artiq/gateware/targets/sayma_rtm.py
+++ b/artiq/gateware/targets/sayma_rtm.py
@@ -77,6 +77,10 @@ class SaymaRTM(Module):
         self.crg.cd_sys.clk.attr.add("keep")
         clk_freq = 125e6
         platform.add_period_constraint(self.crg.cd_sys.clk, 8.0)
+        platform.add_period_constraint(self.crg.cd_clk200.clk, 5.0)
+        platform.add_false_path_constraints(
+            self.crg.cd_sys.clk,
+            self.crg.cd_clk200.clk)
 
         self.submodules.rtm_identifier = RTMIdentifier()
         csr_devices.append("rtm_identifier")