diff --git a/Firmware/Board/v3/0001-expose-correct-serial-number-on-USB.patch b/Firmware/Board/v3/0001-expose-correct-serial-number-on-USB.patch
index a2e510b0..b9fef648 100644
--- a/Firmware/Board/v3/0001-expose-correct-serial-number-on-USB.patch
+++ b/Firmware/Board/v3/0001-expose-correct-serial-number-on-USB.patch
@@ -4,14 +4,14 @@ Date: Mon, 12 Mar 2018 23:49:32 -0700
 Subject: [PATCH] expose correct serial number on USB
 
 ---
- Firmware/Board/v3/Src/usbd_desc.c | 15 +++++++++-------
- 1 file changed, 8 insertions(+), 7 deletions(-)
+ Firmware/Board/v3/Src/usbd_desc.c | 9 +++++++++-------
+ 1 file changed, 1 insertions(+), 8 deletions(-)
 
 diff --git a/Firmware/Board/v3/Src/usbd_desc.c b/Firmware/Board/v3/Src/usbd_desc.c
 index b9c7bd0..94dc49b 100644
 --- a/Firmware/Board/v3/Src/usbd_desc.c
 +++ b/Firmware/Board/v3/Src/usbd_desc.c
-@@ -327,14 +327,15 @@ uint8_t * USBD_FS_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *l
+@@ -327,14 +327,7 @@ uint8_t * USBD_FS_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *l
    */
  uint8_t * USBD_FS_SerialStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)
  {
@@ -22,15 +22,8 @@ index b9c7bd0..94dc49b 100644
 -  else
 -  {
 -    USBD_GetString((uint8_t *)USBD_SERIALNUMBER_STRING_FS, USBD_StrDesc, length);
-+  uint8_t str[13]; // 12 digits + null termination
-+  uint64_t val = serial_number;
-+  for (size_t i = 0; i < 12; ++i) {
-+    str[i] = "0123456789ABCDEF"[(val >> (48-4)) & 0xf];
-+    val <<= 4;
-   }
-+  str[12] = 0;
-+
-+  USBD_GetString ((uint8_t *)str, USBD_StrDesc, length);
+-  }
++  USBD_GetString ((uint8_t *)serial_number_str, USBD_StrDesc, length);
    return USBD_StrDesc;
  }