diff --git a/src/gateware/kasli_soc.py b/src/gateware/kasli_soc.py
index 477cb71..63cb0a0 100755
--- a/src/gateware/kasli_soc.py
+++ b/src/gateware/kasli_soc.py
@@ -71,9 +71,12 @@ class GTP125BootstrapClock(Module):
         platform.add_period_constraint(bootstrap_125.p, 8.0)
         self.specials += [
             Instance("IBUFDS_GTE2",
-                p_CLKSWING_CFG="0b11",
                 i_CEB=0,
-                i_I=bootstrap_125.p, i_IB=bootstrap_125.n, o_O=bootstrap_se),
+                i_I=bootstrap_125.p, i_IB=bootstrap_125.n, 
+                o_O=bootstrap_se,
+                p_CLKCM_CFG="TRUE",
+                p_CLKRCV_TRST="TRUE",
+                p_CLKSWING_CFG=3),
             Instance("BUFG", i_I=bootstrap_se, o_O=self.cd_bootstrap.clk)
         ]
 
diff --git a/src/gateware/zc706.py b/src/gateware/zc706.py
index 4d0fc19..20f4d94 100755
--- a/src/gateware/zc706.py
+++ b/src/gateware/zc706.py
@@ -149,9 +149,9 @@ class ZC706(SoCCore):
                 i_CEB=0,
                 i_I=si5324_out.p, i_IB=si5324_out.n,
                 o_O=cdr_clk,
-                p_CLKCM_CFG="0b1",
-                p_CLKRCV_TRST="0b1",
-                p_CLKSWING_CFG="0b11"),
+                p_CLKCM_CFG="TRUE",
+                p_CLKRCV_TRST="TRUE",
+                p_CLKSWING_CFG=3),
             Instance("BUFG", i_I=cdr_clk, o_O=cdr_clk_buf)
         ]
         self.rustc_cfg["has_si5324"] = None