diff --git a/doc/user-guides/hv-parameters.rst b/doc/user-guides/hv-parameters.rst
index 4dd38e957..d803f993f 100644
--- a/doc/user-guides/hv-parameters.rst
+++ b/doc/user-guides/hv-parameters.rst
@@ -13,7 +13,11 @@ The ACRN hypervisor supports the following parameter:
 +=================+=============================+========================================================================================+
 |                 | disabled                    | This disables the serial port completely.                                              |
 |                 +-----------------------------+----------------------------------------------------------------------------------------+
-| ``uart=``       | bdf@<BDF value>             | This sets the serial port PCI BDF, e.g. ``bdf@0:18.1``                                 |
+| ``uart=``       | bdf@<BDF value>             | This sets the serial port PCI BDF (in HEX), e.g. ``bdf@0xc1``                          |
+|                 |                             |                                                                                        |
+|                 |                             | BDF: Bus, Device, and Function (in HEX) of the serial PCI device. The BDF is packed    |
+|                 |                             | into a 16-bit WORD with format (B:8, D:5, F:3). For example, PCI device ``0:18.1``     |
+|                 |                             | becomes ``0xc1``                                                                       |
 |                 +-----------------------------+----------------------------------------------------------------------------------------+
 |                 | port@<port address>         | This sets the serial port PIO address, e.g. ``uart=port@0x3F8``                        |
 |                 +-----------------------------+----------------------------------------------------------------------------------------+
@@ -30,7 +34,7 @@ For example:
       insmod part_gpt
       insmod ext2
       echo 'Loading ACRN hypervisor ...'
-      multiboot --quirk-modules-after-kernel /boot/acrn.32.out uart=bdf@0:18.1
+      multiboot --quirk-modules-after-kernel /boot/acrn.32.out uart=bdf@0xc1
       module /boot/bzImage Linux_bzImage
       module /boot/bzImage2 Linux_bzImage2
    }
diff --git a/hypervisor/debug/dbg_cmd.c b/hypervisor/debug/dbg_cmd.c
index 53c9bd384..6f9cc9ca2 100644
--- a/hypervisor/debug/dbg_cmd.c
+++ b/hypervisor/debug/dbg_cmd.c
@@ -20,7 +20,7 @@ static struct uart_cmd {
 	int type;
 } cmd_list[] = {
 	{ "uart=port@",	PIO },	/* uart=port@0x3F8 */
-	{ "uart=bdf@",	PCI },	/* uart=bdf@0:18.2 */
+	{ "uart=bdf@",	PCI },	/* uart=bdf@0xc1 */
 	{ "uart=mmio@",	MMIO },	/* uart=mmio@0xfe040000 */
 	{ "uart=disabled", INVALID }
 };