diff --git a/doc/notes/hci_commands_used_le.txt b/doc/notes/hci_commands_used_le.txt
index 735630d14..5af869ee3 100644
--- a/doc/notes/hci_commands_used_le.txt
+++ b/doc/notes/hci_commands_used_le.txt
@@ -3,16 +3,16 @@ hci_le_add_device_to_white_list
 hci_le_connection_update
 hci_le_create_connection
 hci_le_create_connection_cancel
-hci_le_encrypt
+hci_le_encrypt 							32
 hci_le_long_term_key_negative_reply
-hci_le_long_term_key_request_reply
+hci_le_long_term_key_request_reply      18
 hci_le_rand
 hci_le_read_buffer_size
 hci_le_read_white_list_size
 hci_le_remove_device_from_white_list
 hci_le_set_advertise_enable
 hci_le_set_advertising_data
-hci_le_set_advertising_parameters
+hci_le_set_advertising_parameters		16
 hci_le_set_random_address
 hci_le_set_scan_enable
 hci_le_set_scan_parameters
@@ -27,3 +27,5 @@ hci_read_remote_supported_features_command
 hci_reset
 hci_set_event_mask
 hci_write_le_host_supported
+
+max parameter length: 32
diff --git a/src/hci.h b/src/hci.h
index 2d1b8f1f8..ef685c9f8 100644
--- a/src/hci.h
+++ b/src/hci.h
@@ -69,10 +69,26 @@ extern "C" {
 #endif
      
 // packet buffer sizes
+
+// Max HCI Commadn LE payload size:
+// 64 from LE Generate DHKey command
+// 32 from LE Encrypt command
+#if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT)
+#define HCI_CMD_PAYLOAD_SIZE_LE 64
+#else
+#define HCI_CMD_PAYLOAD_SIZE_LE 32
+#endif
+
 // HCI_ACL_PAYLOAD_SIZE is configurable and defined in config.h
 // addition byte in even to terminate remote name request with '\0'
 #define HCI_EVENT_BUFFER_SIZE      (HCI_EVENT_HEADER_SIZE + HCI_EVENT_PAYLOAD_SIZE + 1)
+
+#ifdef ENABLE_CLASSIC
 #define HCI_CMD_BUFFER_SIZE        (HCI_CMD_HEADER_SIZE   + HCI_CMD_PAYLOAD_SIZE)
+#else
+#define HCI_CMD_BUFFER_SIZE        (HCI_CMD_HEADER_SIZE   + HCI_CMD_PAYLOAD_SIZE_LE)
+#endif
+
 #define HCI_ACL_BUFFER_SIZE        (HCI_ACL_HEADER_SIZE   + HCI_ACL_PAYLOAD_SIZE)
     
 // size of hci buffers, big enough for command, event, or acl packet without H4 packet type
diff --git a/src/hci_cmd.c b/src/hci_cmd.c
index fb7db4914..30b97be7f 100644
--- a/src/hci_cmd.c
+++ b/src/hci_cmd.c
@@ -46,6 +46,7 @@
 #include "classic/sdp_util.h"
 #include "hci.h"
 #include "hci_cmd.h"
+#include "btstack_debug.h"
 
 #include <string.h>
 
@@ -578,12 +579,14 @@ const hci_cmd_t hci_delete_stored_link_key = {
 OPCODE(OGF_CONTROLLER_BASEBAND, 0x12), "B1"
 };
 
+#ifdef ENABLE_CLASSIC
 /**
  * @param local_name (UTF-8, Null Terminated, max 248 octets)
  */
 const hci_cmd_t hci_write_local_name = {
 OPCODE(OGF_CONTROLLER_BASEBAND, 0x13), "N"
 };
+#endif
 
 /**
  */
@@ -1052,6 +1055,7 @@ OPCODE(OGF_LE_CONTROLLER, 0x25), ""
 //  LE Read Local P-256 Public Key Complete is generated on completion
 };
 
+#ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT
 /**
  * @param end_test_cmd
  */
@@ -1059,6 +1063,7 @@ const hci_cmd_t hci_le_generate_dhkey = {
 OPCODE(OGF_LE_CONTROLLER, 0x26), "QQ"
 // LE Generate DHKey Complete is generated on completion
 };
+#endif
 
 #endif