diff --git a/procedures/p9/start_host.cpp b/procedures/p9/start_host.cpp
index a31503b..6494086 100644
--- a/procedures/p9/start_host.cpp
+++ b/procedures/p9/start_host.cpp
@@ -66,7 +66,7 @@
     //Kick off the SBE to start the boot
 
     //First ensure ISTEP stepping isn't enabled
-    writeReg(master, P9_SCRATCH_REGISTER_8, 0x20000000);
+    writeRegWithMask(master, P9_SCRATCH_REGISTER_8, 0x20000000, 0x20000000);
 
     //Start the SBE
     writeRegWithMask(master, P9_CBS_CS, 0x80000000, 0x80000000);
@@ -76,4 +76,3 @@
 
 }
 }
-