diff --git a/fast-servo/pyfastservo/si5340.py b/fast-servo/pyfastservo/si5340.py
index 67132be..2cc5b74 100644
--- a/fast-servo/pyfastservo/si5340.py
+++ b/fast-servo/pyfastservo/si5340.py
@@ -35,6 +35,15 @@ STATUS_LOSREF = 0x04
 STATUS_LOL = 0x08
 
 
+def write_register(bus, address, value):
+    page = address >> 8
+    register = address & 0xFF
+    bus.write_byte_data(IC_ADDR, 0x01, page)
+    try:
+        bus.write_byte_data(IC_ADDR, register, value)
+    except Exception as e:
+        raise Exception(f"Write failed 0x{value:02X} at 0x{address:04X}: {e}")
+
 def write_preamble(bus):
     preamble = [
         (0x0B24, 0xC0),
@@ -45,7 +54,7 @@ def write_preamble(bus):
         (0x0B4E, 0x1A),
     ]
     for address, value in preamble:
-        bus.write_byte_data(IC_ADDR, address, value)
+        write_register(bus, address, value)
 
 def write_postamble(bus):
     postamble = [
@@ -54,7 +63,7 @@ def write_postamble(bus):
         (0x0B25, 0x02),
     ]
     for address, value in postamble:
-        bus.write_byte_data(IC_ADDR, address, value)
+        write_register(bus, address, value)
 
 def wait_device_ready(bus):
     for _ in range(15):
@@ -244,7 +253,7 @@ def configure_si5340():
 
         print("Writing main configuration...")
         for address, value in main_config:
-            bus.write_byte_data(IC_ADDR, address, value)
+            write_register(bus, address, value)
         print("Main configuration written")
 
         write_postamble(bus)