diff --git a/hardware/test/si5351-configure.py b/hardware/test/si5351-configure.py
index 3d130b15..b9f25d11 100644
--- a/hardware/test/si5351-configure.py
+++ b/hardware/test/si5351-configure.py
@@ -197,7 +197,7 @@ write_registers(92, 0x00)
 #   CLK4_INV=0 (not inverted)
 #   CLK4_SRC=3 (MS4 as input source)
 #   CLK4_IDRV=3 (8mA)
-write_registers(16, (0x4F, 0x4B, 0x4B, 0x4B, 0x0F, 0x80, 0xC0, 0xC0))
+write_registers(16, (0x0F, 0x0B, 0x0B, 0x0B, 0x0F, 0x80, 0xC0, 0xC0))
 
 # Enable CLK outputs 0, 1, 4 only.
 write_registers(3, 0xFF ^ 0b00011111)