diff --git a/app/uart.c b/app/uart.c
index b878d1d..87aba88 100644
--- a/app/uart.c
+++ b/app/uart.c
@@ -210,29 +210,26 @@ static void SendVersion(void)
     SendReply(&Reply, sizeof(Reply));
 }
 
+#ifndef ENABLE_FEAT_F4HWN
 static bool IsBadChallenge(const uint32_t *pKey, const uint32_t *pIn, const uint32_t *pResponse)
 {
-    #ifdef ENABLE_FEAT_F4HWN
-        UNUSED(pKey);
-        UNUSED(pIn);
-        UNUSED(pResponse);
-    #else
-        unsigned int i;
-        uint32_t     IV[4];
+    unsigned int i;
+    uint32_t     IV[4];
 
-        IV[0] = 0;
-        IV[1] = 0;
-        IV[2] = 0;
-        IV[3] = 0;
+    IV[0] = 0;
+    IV[1] = 0;
+    IV[2] = 0;
+    IV[3] = 0;
 
-        AES_Encrypt(pKey, IV, pIn, IV, true);
+    AES_Encrypt(pKey, IV, pIn, IV, true);
+
+    for (i = 0; i < 4; i++)
+        if (IV[i] != pResponse[i])
+            return true;
 
-        for (i = 0; i < 4; i++)
-            if (IV[i] != pResponse[i])
-                return true;
-    #endif
     return false;
 }
+#endif
 
 // session init, sends back version info and state
 // timestamp is a session id really
@@ -360,6 +357,7 @@ static void CMD_0529(void)
     SendReply(&Reply, sizeof(Reply));
 }
 
+#ifndef ENABLE_FEAT_F4HWN
 static void CMD_052D(const uint8_t *pBuffer)
 {
     const CMD_052D_t *pCmd = (const CMD_052D_t *)pBuffer;
@@ -400,6 +398,7 @@ static void CMD_052D(const uint8_t *pBuffer)
 
     SendReply(&Reply, sizeof(Reply));
 }
+#endif
 
 // session init, sends back version info and state
 // timestamp is a session id really
@@ -600,10 +599,12 @@ void UART_HandleCommand(void)
         case 0x0529:
             CMD_0529();
             break;
-    
-        case 0x052D:
-            CMD_052D(UART_Command.Buffer);
-            break;
+            
+        #ifndef ENABLE_FEAT_F4HWN
+            case 0x052D:
+                CMD_052D(UART_Command.Buffer);
+                break;
+        #endif
     
         case 0x052F:
             CMD_052F(UART_Command.Buffer);
diff --git a/settings.c b/settings.c
index f9bb641..beb582e 100644
--- a/settings.c
+++ b/settings.c
@@ -326,17 +326,19 @@ void SETTINGS_InitEEPROM(void)
         gMR_ChannelExclude[i] = false;
     }
 
-    // 0F30..0F3F
-    EEPROM_ReadBuffer(0x0F30, gCustomAesKey, sizeof(gCustomAesKey));
-    bHasCustomAesKey = false;
-    for (unsigned int i = 0; i < ARRAY_SIZE(gCustomAesKey); i++)
-    {
-        if (gCustomAesKey[i] != 0xFFFFFFFFu)
-        {
-            bHasCustomAesKey = true;
-            return;
-        }
-    }
+        // 0F30..0F3F
+        EEPROM_ReadBuffer(0x0F30, gCustomAesKey, sizeof(gCustomAesKey));
+        bHasCustomAesKey = false;
+        #ifndef ENABLE_FEAT_F4HWN
+            for (unsigned int i = 0; i < ARRAY_SIZE(gCustomAesKey); i++)
+            {
+                if (gCustomAesKey[i] != 0xFFFFFFFFu)
+                {
+                    bHasCustomAesKey = true;
+                    return;
+                }
+            }
+        #endif
 
     #ifdef ENABLE_FEAT_F4HWN
         // 1FF0..0x1FF7