diff --git a/monitor/bt.h b/monitor/bt.h
index 430ebcd..fb40e0f 100644
--- a/monitor/bt.h
+++ b/monitor/bt.h
@@ -309,6 +309,24 @@ struct bt_hci_cmd_disconn_logic_link {
 	uint16_t handle;
 } __attribute__ ((packed));
 
+#define BT_HCI_CMD_LOGIC_LINK_CANCEL		0x043b
+struct bt_hci_cmd_logic_link_cancel {
+	uint8_t  phy_handle;
+	uint8_t  flow_spec;
+} __attribute__ ((packed));
+struct bt_hci_rsp_logic_link_cancel {
+	uint8_t  status;
+	uint8_t  phy_handle;
+	uint8_t  flow_spec;
+} __attribute__ ((packed));
+
+#define BT_HCI_CMD_FLOW_SPEC_MODIFY		0x043c
+struct bt_hci_cmd_flow_spec_modify {
+	uint16_t handle;
+	uint8_t  tx_flow_spec[16];
+	uint8_t  rx_flow_spec[16];
+} __attribute__ ((packed));
+
 #define BT_HCI_CMD_HOLD_MODE			0x0801
 struct bt_hci_cmd_hold_mode {
 	uint16_t handle;
diff --git a/monitor/packet.c b/monitor/packet.c
index 64037e8..94539e6 100644
--- a/monitor/packet.c
+++ b/monitor/packet.c
@@ -2006,6 +2006,32 @@ static void disconn_logic_link_cmd(const void *data, uint8_t size)
 	print_handle(cmd->handle);
 }
 
+static void logic_link_cancel_cmd(const void *data, uint8_t size)
+{
+	const struct bt_hci_cmd_logic_link_cancel *cmd = data;
+
+	print_phy_handle(cmd->phy_handle);
+	print_field("TX flow spec: 0x%2.2x", cmd->flow_spec);
+}
+
+static void logic_link_cancel_rsp(const void *data, uint8_t size)
+{
+        const struct bt_hci_rsp_logic_link_cancel *rsp = data;
+
+	print_status(rsp->status);
+	print_phy_handle(rsp->phy_handle);
+	print_field("TX flow spec: 0x%2.2x", rsp->flow_spec);
+}
+
+static void flow_spec_modify_cmd(const void *data, uint8_t size)
+{
+	const struct bt_hci_cmd_flow_spec_modify *cmd = data;
+
+	print_handle(cmd->handle);
+
+	packet_hexdump(data + 2, size - 2);
+}
+
 static void hold_mode_cmd(const void *data, uint8_t size)
 {
 	const struct bt_hci_cmd_hold_mode *cmd = data;
@@ -3012,8 +3038,11 @@ static const struct opcode_data opcode_table[] = {
 				accept_logic_link_cmd, 33, true },
 	{ 0x043a, "Disconnect Logical Link",
 				disconn_logic_link_cmd, 2, true },
-	{ 0x043b, "Logical Link Cancel"			},
-	{ 0x043c, "Flow Specifcation Modify"		},
+	{ 0x043b, "Logical Link Cancel",
+				logic_link_cancel_cmd, 2, true,
+				logic_link_cancel_rsp, 3, true },
+	{ 0x043c, "Flow Specifcation Modify",
+				flow_spec_modify_cmd, 34, true },
 
 	/* OGF 2 - Link Policy */
 	{ 0x0801, "Holde Mode",