diff --git a/reactos/sdk/lib/rtl/unicode.c b/reactos/sdk/lib/rtl/unicode.c
index 41c9a99b065..655c04d16c3 100644
--- a/reactos/sdk/lib/rtl/unicode.c
+++ b/reactos/sdk/lib/rtl/unicode.c
@@ -1295,6 +1295,21 @@ RtlIsTextUnicode(CONST VOID* buf, INT len, INT* pf)
 
         last_lo_byte = lo_byte;
         last_hi_byte = hi_byte;
+
+        switch (s[i])
+        {
+            case 0xFFFE: /* Reverse BOM */
+            case UNICODE_NULL:
+            case 0x0A0D: /* ASCII CRLF (packed into one word) */
+            case 0xFFFF: /* Unicode 0xFFFF */
+                out_flags |= IS_TEXT_UNICODE_ILLEGAL_CHARS;
+                break;
+        }
+    }
+
+    if (lo_byte_diff < 127 && !hi_byte_diff)
+    {
+        out_flags |= IS_TEXT_UNICODE_ASCII16;
     }
 
     if (NlsMbCodePageTag)
diff --git a/rostests/apitests/advapi32/IsTextUnicode.c b/rostests/apitests/advapi32/IsTextUnicode.c
index 7bd278509af..c4c8162c7df 100644
--- a/rostests/apitests/advapi32/IsTextUnicode.c
+++ b/rostests/apitests/advapi32/IsTextUnicode.c
@@ -80,7 +80,7 @@ START_TEST(IsTextUnicode)
         NEW_TEST(L"\xFFFE" L"UNICODE String 5 Привет!", IS_TEXT_UNICODE_STATISTICS, 0, FALSE),
         NEW_TEST(L"\xFFFE" L"UNICODE String 5 Привет!", INVALID_FLAG, 0, FALSE),
 
-        // 28
+        // 31
         /* Reverse BOM */
         NEW_TEST(L"UNICODE S" L"\xFFFE" L"tring 5 Привет!", IS_TEXT_UNICODE_ILLEGAL_CHARS, IS_TEXT_UNICODE_ILLEGAL_CHARS, FALSE),
         /* UNICODE_NUL */