diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c3f36d41..7369745 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -662,15 +662,28 @@
 	char *p = mac_addr;
 	int i;
 	char separator;
+	bool reversed = false;
 
-	if (fmt[1] == 'F') {		/* FDDI canonical format */
+	switch (fmt[1]) {
+	case 'F':
 		separator = '-';
-	} else {
+		break;
+
+	case 'R':
+		reversed = true;
+		/* fall through */
+
+	default:
 		separator = ':';
+		break;
 	}
 
 	for (i = 0; i < 6; i++) {
-		p = hex_byte_pack(p, addr[i]);
+		if (reversed)
+			p = hex_byte_pack(p, addr[5 - i]);
+		else
+			p = hex_byte_pack(p, addr[i]);
+
 		if (fmt[0] == 'M' && i != 5)
 			*p++ = separator;
 	}
@@ -933,6 +946,7 @@
  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
  *       with a dash-separated hex notation
+ * - '[mM]R For a 6-byte MAC address, Reverse order (Bluetooth)
  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
@@ -995,7 +1009,8 @@
 		return resource_string(buf, end, ptr, spec, fmt);
 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
 	case 'm':			/* Contiguous: 000102030405 */
-					/* [mM]F (FDDI, bit reversed) */
+					/* [mM]F (FDDI) */
+					/* [mM]R (Reverse order; Bluetooth) */
 		return mac_address_string(buf, end, ptr, spec, fmt);
 	case 'I':			/* Formatted IP supported
 					 * 4:	1.2.3.4