diff --git a/common/src/lx_nor_flash_extended_cache_enable.c b/common/src/lx_nor_flash_extended_cache_enable.c
index 7bd2863..b71b01c 100644
--- a/common/src/lx_nor_flash_extended_cache_enable.c
+++ b/common/src/lx_nor_flash_extended_cache_enable.c
@@ -9,6 +9,8 @@
  * SPDX-License-Identifier: MIT
  **************************************************************************/
 
+// Some portions generated by Codex (GPT-5).
+
 
 /**************************************************************************/
 /**************************************************************************/
@@ -93,8 +95,11 @@ ULONG   block_word;
 #endif
 
 
+    /* Calculate cache size in words.  */
+    cache_size = size / sizeof(ULONG);
+
     /* Determine if memory was specified but with an invalid size (less than one NOR sector).  */
-    if ((memory) && (size < LX_NOR_SECTOR_SIZE))
+    if ((memory) && (cache_size < LX_NOR_SECTOR_SIZE))
     {
 
         /* Error in memory size supplied.  */
@@ -110,9 +115,6 @@ ULONG   block_word;
     /* Initialize the internal NOR cache.  */
     nor_flash -> lx_nor_flash_extended_cache_entries =  0;
 
-    /* Calculate cache size in words.  */
-    cache_size = size/sizeof(ULONG);
-
     /* Setup cache memory pointer.  */
     cache_memory =  (ULONG *) memory;
 
@@ -317,5 +319,3 @@ ULONG   block_word;
     return(LX_DISABLED);
 #endif
 }
-
-
diff --git a/test/regression/levelx_nor_flash_test_cache.c b/test/regression/levelx_nor_flash_test_cache.c
index d0b24d0..bb5be1b 100644
--- a/test/regression/levelx_nor_flash_test_cache.c
+++ b/test/regression/levelx_nor_flash_test_cache.c
@@ -9,6 +9,8 @@
 /* SPDX-License-Identifier: MIT                                            */
 /***************************************************************************/
 
+// Some portions generated by Codex (GPT-5).
+
 /* Basic NOR flash tests...  */
 
 #include <stdio.h>
@@ -31,6 +33,7 @@ ULONG           readbuffer[128];
 
 UCHAR   nor_cache_memory[2048+16+8];
 UCHAR   nor_cache_memory2[8192];
+UCHAR   nor_cache_memory_invalid[256];
 
 
 /* Define LevelX NOR flash simulator prototoypes.  */
@@ -1592,7 +1595,25 @@ status += lx_nor_flash_extended_cache_enable(&nor_sim_flash, nor_cache_memory, s
     /* Open the flash.  */
     status =  lx_nor_flash_open(&nor_sim_flash, "sim nor flash", _lx_nor_flash_simulator_initialize);
 #ifndef LX_NOR_DISABLE_EXTENDED_CACHE
-status += lx_nor_flash_extended_cache_enable(&nor_sim_flash, nor_cache_memory2, sizeof(nor_cache_memory2));
+    if (status == LX_SUCCESS)
+    {
+
+        status =  lx_nor_flash_extended_cache_enable(&nor_sim_flash, nor_cache_memory_invalid, sizeof(nor_cache_memory_invalid));
+
+        if (status != LX_ERROR)
+        {
+
+              printf("FAILED!\n");
+#ifdef BATCH_TEST
+        exit(1);
+#endif
+              while(1)
+              {
+              }
+        }
+
+        status =  lx_nor_flash_extended_cache_enable(&nor_sim_flash, nor_cache_memory2, sizeof(nor_cache_memory2));
+    }
 #endif
 
     if (status != LX_SUCCESS)
@@ -1668,5 +1689,3 @@ status += lx_nor_flash_extended_cache_enable(&nor_sim_flash, nor_cache_memory2,
      {
      }
 }
-
-