diff --git a/examples/device/hid_cdc_passkey/src/main.c b/examples/device/hid_cdc_passkey/src/main.c
index 2b6612db2..f0b7fa3d9 100644
--- a/examples/device/hid_cdc_passkey/src/main.c
+++ b/examples/device/hid_cdc_passkey/src/main.c
@@ -77,6 +77,12 @@ static const char* help_str[] = {
   "l set keyboard layout\r\n",
 };
 
+static const char* prog_str[] = {
+  "K set manufacturer key\r\n",
+  "L lock device\r\n",
+  "E erase firmware\r\n",
+};
+
 enum {
   MENU_HOME,
   MENU_USER,
@@ -116,6 +122,13 @@ uint32_t board_button2_read(void)
   return BUTTON2_STATE_ACTIVE == HAL_GPIO_ReadPin(BUTTON2_PORT, BUTTON2_PIN);
 }
 
+static bool locked(void)
+{  
+  FLASH_OBProgramInitTypeDef ob;
+  HAL_FLASHEx_OBGetConfig(&ob);
+  return (OB_RDP_LEVEL_2 == ob.RDPLevel);
+}
+
 static void clear_credentials(void)
 {
   // clear credentials
@@ -419,57 +432,42 @@ void cdc_task(void)
               break;
             // hidden menu
             case 'K': // set manufacturer key
-              {
-                FLASH_OBProgramInitTypeDef ob;
-                HAL_FLASHEx_OBGetConfig(&ob);
-                if (OB_RDP_LEVEL_2 == ob.RDPLevel) {
-                  str = "\r\ndevice locked\r\n";
-                } else {
-                  i = 0; // reset index
-                  menu = MENU_MANUF;
-                  str = "\r\nenter manufacturer key (up to 32 char): ";
-                }
+              if (!locked()) {
+                i = 0; // reset index
+                menu = MENU_MANUF;
+                str = "\r\nenter manufacturer key (up to 32 char): ";
               }
               break;
             case 'L': // lock device
-              {
+              if (!locked()) {
+                tud_cdc_write_str_flush("\r\nlocking device\r\n");
                 FLASH_OBProgramInitTypeDef ob;
                 HAL_FLASHEx_OBGetConfig(&ob);
-                if (OB_RDP_LEVEL_2 == ob.RDPLevel) {
-                  str = "\r\ndevice locked\r\n";
-                } else {
-                  str = "\r\nlocking device\r\n";
-                  ob.RDPLevel = OB_RDP_LEVEL_2; // level 2, disabling debug, and write protecting option byte
-                  ob.WRPState = OB_WRPSTATE_ENABLE; // write protect pages
-                  ob.WRPPage = 0x7; // all but last sector holding the config
-                  HAL_FLASH_Unlock();
-                  HAL_FLASH_OB_Unlock();
-                  //HAL_FLASHEx_OBProgram(&ob);
-                  HAL_FLASH_OB_Lock();
-                  HAL_FLASH_Lock();
-                  HAL_FLASH_OB_Launch();
-                }
+                ob.RDPLevel = OB_RDP_LEVEL_2; // level 2, disabling debug, and write protecting option byte
+                ob.WRPState = OB_WRPSTATE_ENABLE; // write protect pages
+                ob.WRPPage = 0x7; // all but last sector holding the config
+                HAL_FLASH_Unlock();
+                HAL_FLASH_OB_Unlock();
+                //HAL_FLASHEx_OBProgram(&ob);
+                HAL_FLASH_OB_Lock();
+                HAL_FLASH_Lock();
+                HAL_FLASH_OB_Launch();
               }
               break;
             case 'E': // mass erase to restart STM32 bootloader
-              {
-
-                FLASH_OBProgramInitTypeDef ob;
-                HAL_FLASHEx_OBGetConfig(&ob);
-                if (OB_RDP_LEVEL_2 == ob.RDPLevel) {
-                  str = "\r\ncan't mass erase: device locked\r\n";
-                } else {
-                  HAL_FLASH_Unlock();
-                  FLASH_EraseInitTypeDef EraseInitStruct;
-                  EraseInitStruct.TypeErase   = FLASH_TYPEERASE_MASSERASE;
-                  uint32_t error;
-                  if (HAL_FLASHEx_Erase(&EraseInitStruct, &error) != HAL_OK) {
-                    printf("mass earse failed\r\n");
-                  }
-                  HAL_FLASH_Lock();
-                  HAL_FLASH_OB_Launch(); // just to restart
+              if (!locked()) {
+                tud_cdc_write_str_flush("\r\nerasing firmware\r\n");
+                HAL_FLASH_Unlock();
+                FLASH_EraseInitTypeDef EraseInitStruct;
+                EraseInitStruct.TypeErase   = FLASH_TYPEERASE_MASSERASE;
+                uint32_t error;
+                if (HAL_FLASHEx_Erase(&EraseInitStruct, &error) != HAL_OK) {
+                  printf("mass earse failed\r\n");
                 }
+                HAL_FLASH_Lock();
+                HAL_FLASH_OB_Launch(); // just to restart
               }
+              break;
             case '\r':
             case '\n':
               break; // nothing to do
@@ -481,6 +479,11 @@ void cdc_task(void)
               for (uint8_t j = 0; j < LENGTH(help_str); j++) {
                 tud_cdc_write_str_flush(help_str[j]);
               }
+              if (!locked()) {
+                for (uint8_t j = 0; j < LENGTH(prog_str); j++) {
+                  tud_cdc_write_str_flush(prog_str[j]);
+                }
+              }
           }
           break;
         case MENU_USER: