diff --git a/src/lpc176x/Makefile b/src/lpc176x/Makefile
index 0935158a..b9fd454f 100644
--- a/src/lpc176x/Makefile
+++ b/src/lpc176x/Makefile
@@ -19,7 +19,8 @@ src-y += ../lib/lpc176x/device/system_LPC17xx.c
 src-$(CONFIG_HAVE_GPIO_ADC) += lpc176x/adc.c
 src-$(CONFIG_HAVE_GPIO_I2C) += lpc176x/i2c.c
 src-$(CONFIG_HAVE_GPIO_SPI) += lpc176x/spi.c
-src-$(CONFIG_USBSERIAL) += lpc176x/usbserial.c generic/usb_cdc.c
+src-$(CONFIG_USBSERIAL) += lpc176x/usbserial.c lpc176x/chipid.c
+src-$(CONFIG_USBSERIAL) += generic/usb_cdc.c
 src-$(CONFIG_SERIAL) += lpc176x/serial.c generic/serial_irq.c
 
 # Build the additional bin output file
diff --git a/src/lpc176x/chipid.c b/src/lpc176x/chipid.c
new file mode 100644
index 00000000..80b80619
--- /dev/null
+++ b/src/lpc176x/chipid.c
@@ -0,0 +1,46 @@
+// Support for extracting the hardware chip id on lpc176x
+//
+// Copyright (C) 2019  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "autoconf.h" // CONFIG_USB_SERIAL_NUMBER_CHIPID
+#include "generic/irq.h" // irq_disable
+#include "generic/usb_cdc.h" // usb_fill_serial
+#include "generic/usbstd.h" // usb_string_descriptor
+#include "sched.h" // DECL_INIT
+
+// IAP interface
+#define IAP_LOCATION        0x1fff1ff1
+#define IAP_CMD_READ_UID    58
+#define IAP_UID_LEN         16
+typedef void (*IAP)(uint32_t *, uint32_t *);
+
+static struct {
+    struct usb_string_descriptor desc;
+    uint16_t data[IAP_UID_LEN * 2];
+} cdc_chipid;
+
+struct usb_string_descriptor *
+usbserial_get_serialid(void)
+{
+   return &cdc_chipid.desc;
+}
+
+void
+chipid_init(void)
+{
+    if (!CONFIG_USB_SERIAL_NUMBER_CHIPID)
+        return;
+
+    uint32_t iap_cmd_uid[5] = {IAP_CMD_READ_UID, 0, 0, 0, 0};
+    uint32_t iap_resp[5];
+    IAP iap_entry = (IAP)IAP_LOCATION;
+    irq_disable();
+    iap_entry(iap_cmd_uid, iap_resp);
+    irq_enable();
+
+    usb_fill_serial(&cdc_chipid.desc, ARRAY_SIZE(cdc_chipid.data)
+                    , &iap_resp[1]);
+}
+DECL_INIT(chipid_init);
diff --git a/src/lpc176x/usbserial.c b/src/lpc176x/usbserial.c
index 6e1cd77b..95ce6e74 100644
--- a/src/lpc176x/usbserial.c
+++ b/src/lpc176x/usbserial.c
@@ -13,7 +13,6 @@
 #include "byteorder.h" // cpu_to_le32
 #include "command.h" // DECL_CONSTANT_STR
 #include "generic/usb_cdc.h" // usb_notify_ep0
-#include "generic/usbstd.h" // usb_string_descriptor
 #include "internal.h" // gpio_peripheral
 #include "sched.h" // DECL_INIT
 #include "usb_cdc_ep.h" // USB_CDC_EP_BULK_IN
@@ -35,12 +34,6 @@
 #define RD_EN (1<<0)
 #define WR_EN (1<<1)
 
-// IAP interface
-#define IAP_LOCATION        0x1fff1ff1
-#define IAP_CMD_READ_UID    58
-#define IAP_UID_LEN         16
-typedef void (*IAP)(uint32_t *, uint32_t *);
-
 static void
 usb_irq_disable(void)
 {
@@ -267,39 +260,11 @@ usb_request_bootloader(void)
     NVIC_SystemReset();
 }
 
-static struct {
-    struct usb_string_descriptor desc;
-    uint16_t data[IAP_UID_LEN * 2];
-} cdc_chipid;
-
-struct usb_string_descriptor *
-usbserial_get_serialid(void)
-{
-   return &cdc_chipid.desc;
-}
-
 
 /****************************************************************
  * Setup and interrupts
  ****************************************************************/
 
-static void
-usb_set_serial(void)
-{
-    if (!CONFIG_USB_SERIAL_NUMBER_CHIPID)
-        return;
-
-    uint32_t iap_cmd_uid[5] = {IAP_CMD_READ_UID, 0, 0, 0, 0};
-    uint32_t iap_resp[5];
-    IAP iap_entry = (IAP)IAP_LOCATION;
-    __disable_irq();
-    iap_entry(iap_cmd_uid, iap_resp);
-    __enable_irq();
-
-    usb_fill_serial(&cdc_chipid.desc, ARRAY_SIZE(cdc_chipid.data)
-                    , &iap_resp[1]);
-}
-
 void
 USB_IRQHandler(void)
 {
@@ -335,8 +300,6 @@ DECL_CONSTANT_STR("RESERVE_PINS_USB", "P0.30,P0.29,P2.9");
 void
 usbserial_init(void)
 {
-    usb_set_serial();
-
     usb_irq_disable();
     // enable power
     enable_pclock(PCLK_USB);