diff --git a/litellm/litellm_core_utils/prompt_templates/factory.py b/litellm/litellm_core_utils/prompt_templates/factory.py
index 9deb3fd0ab6..746745cc791 100644
--- a/litellm/litellm_core_utils/prompt_templates/factory.py
+++ b/litellm/litellm_core_utils/prompt_templates/factory.py
@@ -883,10 +883,10 @@ _CHARSET_AWARE_MEDIA_TYPE: Final = "text/plain"
 
 
 def _media_type_with_original_parameters(format_override: str, original_media_type: str) -> str:
-    if format_override.strip() != _CHARSET_AWARE_MEDIA_TYPE:
+    if format_override.strip().lower() != _CHARSET_AWARE_MEDIA_TYPE:
         return format_override
     base_type, separator, parameters = original_media_type.partition(";")
-    if not separator or base_type.strip() != format_override.strip():
+    if not separator or base_type.strip().lower() != format_override.strip().lower():
         return format_override
     return f"{format_override}{separator}{parameters}"
 
diff --git a/tests/unit/litellm_core_utils/prompt_templates/test_litellm_core_utils_prompt_templates_factory.py b/tests/unit/litellm_core_utils/prompt_templates/test_litellm_core_utils_prompt_templates_factory.py
index 4179dafe570..9cb574bada5 100644
--- a/tests/unit/litellm_core_utils/prompt_templates/test_litellm_core_utils_prompt_templates_factory.py
+++ b/tests/unit/litellm_core_utils/prompt_templates/test_litellm_core_utils_prompt_templates_factory.py
@@ -5235,8 +5235,20 @@ _LATIN1_TEXT_DATA_URI = "data:text/plain;charset=iso-8859-1;base64," + base64.b6
             {"type": "image_url", "image_url": {"url": "data:TEXT/PLAIN;base64," + _TEXT_B64}},
             "the secret code word is MANGO\n",
         ),
+        (
+            {"type": "image_url", "image_url": {"url": _LATIN1_TEXT_DATA_URI.replace("text/plain", "TEXT/PLAIN", 1)}},
+            "the secret code word is MANGÓ\n",
+        ),
+    ],
+    ids=[
+        "image_url",
+        "file",
+        "image_url_charset",
+        "file_charset",
+        "file_latin1",
+        "image_url_uppercase",
+        "uppercase_latin1",
     ],
-    ids=["image_url", "file", "image_url_charset", "file_charset", "file_latin1", "image_url_uppercase"],
 )
 def test_anthropic_messages_pt_text_plain_data_uri_becomes_text_source_document(block, expected_text):
     messages = [{"role": "user", "content": [{"type": "text", "text": "What is the code word?"}, block]}]