diff --git a/vndk/tools/header-checker/src/linker/module_merger.cpp b/vndk/tools/header-checker/src/linker/module_merger.cpp
index 2ec368bc9..9b5f31d58 100644
--- a/vndk/tools/header-checker/src/linker/module_merger.cpp
+++ b/vndk/tools/header-checker/src/linker/module_merger.cpp
@@ -206,7 +206,8 @@ ModuleMerger::UpdateUDTypeAccounting(
   std::string added_type_id = addend_node->GetSelfType();
   auto type_id_it = module_->type_graph_.find(added_type_id);
   if (type_id_it != module_->type_graph_.end()) {
-    added_type_id = added_type_id + "#ODR:" + addend_compilation_unit_path;
+    added_type_id = repr::FormatMultiDefinitionTypeId(
+        added_type_id, addend_compilation_unit_path);
   }
 
   // Add the ud-type with type-id to the type_graph_, since if there are generic
@@ -390,7 +391,8 @@ MergeStatus ModuleMerger::MergeReferencingType(
           addend.GetCompilationUnitPath(final_referenced_type);
       // The path is empty for built-in types.
       if (compilation_unit_path != "") {
-        added_type_id = added_type_id + "#ODR:" + compilation_unit_path;
+        added_type_id = repr::FormatMultiDefinitionTypeId(
+            added_type_id, compilation_unit_path);
       }
     }
   }
diff --git a/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp b/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
index 377568c17..a121c3780 100644
--- a/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
+++ b/vndk/tools/header-checker/src/repr/abi_diff_helpers.cpp
@@ -264,8 +264,12 @@ bool AbiDiffHelper::CompareVTables(
 
 bool AbiDiffHelper::AreOpaqueTypesEqual(const std::string &old_type_id,
                                         const std::string &new_type_id) const {
+  // b/253095767: In T, some dump files contain opaque types whose IDs end with
+  // "#ODR:" and the source paths. This function removes the suffixes before
+  // comparing the type IDs.
   if (!diff_policy_options_.consider_opaque_types_different_ ||
-      old_type_id == new_type_id) {
+      ExtractMultiDefinitionTypeId(old_type_id) ==
+          ExtractMultiDefinitionTypeId(new_type_id)) {
     return true;
   }
   // __va_list is an opaque type defined by the compiler. ARM ABI requires
diff --git a/vndk/tools/header-checker/src/repr/ir_representation.h b/vndk/tools/header-checker/src/repr/ir_representation.h
index 01b68bd2a..bcc07ba7c 100644
--- a/vndk/tools/header-checker/src/repr/ir_representation.h
+++ b/vndk/tools/header-checker/src/repr/ir_representation.h
@@ -98,6 +98,16 @@ std::map<V, K> CreateInverseMap(const std::map<K, V> &m) {
   return inverse_map;
 }
 
+static inline std::string FormatMultiDefinitionTypeId(
+    const std::string &type_id, const std::string &compilation_unit_path) {
+  return type_id + "#ODR:" + compilation_unit_path;
+}
+
+static inline std::string_view ExtractMultiDefinitionTypeId(
+    std::string_view type_id) {
+  return type_id.substr(0, type_id.find("#ODR:"));
+}
+
 class LinkableMessageIR {
  public:
   virtual ~LinkableMessageIR() {}
diff --git a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h
index 54686ba13..c45751c50 100644
--- a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h
+++ b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h
@@ -6,4 +6,8 @@ struct Struct {
 
 struct Opaque;
 
-void func(const struct Struct *, const struct Opaque *);
+struct DefinedInOneHeader;
+
+extern "C" {
+void func(Struct *, Opaque *, DefinedInOneHeader *);
+}
diff --git a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h
index 075f78cab..46fd401f6 100644
--- a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h
+++ b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h
@@ -6,4 +6,9 @@ struct Struct {
 
 struct Opaque;
 
-void func(const struct Opaque *, const struct Struct *);
+struct DefinedInOneHeader {};
+
+extern "C" {
+void func(Opaque *, Struct *, DefinedInOneHeader *);
+void func2(DefinedInOneHeader *);
+}
diff --git a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h
new file mode 120000
index 000000000..8023898a6
--- /dev/null
+++ b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h
@@ -0,0 +1 @@
+./def2.h
\ No newline at end of file
diff --git a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/map.txt b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/map.txt
index 654d2c4bf..f75ae402e 100644
--- a/vndk/tools/header-checker/tests/integration/merge_multi_definitions/map.txt
+++ b/vndk/tools/header-checker/tests/integration/merge_multi_definitions/map.txt
@@ -1,5 +1,6 @@
 libmerge_multi_definitions {
   global:
     func;
+    func2;
     var;
 };
diff --git a/vndk/tools/header-checker/tests/module.py b/vndk/tools/header-checker/tests/module.py
index af882ad39..2688a2165 100755
--- a/vndk/tools/header-checker/tests/module.py
+++ b/vndk/tools/header-checker/tests/module.py
@@ -679,6 +679,18 @@ TEST_MODULES = [
         linker_flags=['-output-format', 'Json', '-sources-per-thread', '1'],
         has_reference_dump=True,
     ),
+    LsdumpModule(
+        name='libdiff_multi_definitions',
+        arch='arm64',
+        srcs=[
+            'integration/merge_multi_definitions/include/def1.h',
+            'integration/merge_multi_definitions/include/link_to_def2.h',
+        ],
+        version_script='integration/merge_multi_definitions/map.txt',
+        export_include_dirs=['integration/merge_multi_definitions/include'],
+        linker_flags=['-output-format', 'Json', '-sources-per-thread', '1'],
+        has_reference_dump=True,
+    ),
     LsdumpModule(
         name='libstruct_extensions',
         arch='arm64',
diff --git a/vndk/tools/header-checker/tests/reference_dumps/arm64/libdiff_multi_definitions.so.lsdump b/vndk/tools/header-checker/tests/reference_dumps/arm64/libdiff_multi_definitions.so.lsdump
new file mode 100644
index 000000000..08c944f73
--- /dev/null
+++ b/vndk/tools/header-checker/tests/reference_dumps/arm64/libdiff_multi_definitions.so.lsdump
@@ -0,0 +1,174 @@
+{
+ "array_types" : [],
+ "builtin_types" :
+ [
+  {
+   "alignment" : 1,
+   "is_integral" : true,
+   "is_unsigned" : true,
+   "linker_set_key" : "_ZTIc",
+   "name" : "char",
+   "referenced_type" : "_ZTIc",
+   "self_type" : "_ZTIc",
+   "size" : 1
+  },
+  {
+   "alignment" : 4,
+   "is_integral" : true,
+   "linker_set_key" : "_ZTIi",
+   "name" : "int",
+   "referenced_type" : "_ZTIi",
+   "self_type" : "_ZTIi",
+   "size" : 4
+  },
+  {
+   "linker_set_key" : "_ZTIv",
+   "name" : "void",
+   "referenced_type" : "_ZTIv",
+   "self_type" : "_ZTIv"
+  }
+ ],
+ "elf_functions" :
+ [
+  {
+   "name" : "func"
+  },
+  {
+   "name" : "func2"
+  },
+  {
+   "name" : "var"
+  }
+ ],
+ "elf_objects" : [],
+ "enum_types" : [],
+ "function_types" : [],
+ "functions" :
+ [
+  {
+   "function_name" : "func",
+   "linker_set_key" : "func",
+   "parameters" :
+   [
+    {
+     "referenced_type" : "_ZTIP6Struct"
+    },
+    {
+     "referenced_type" : "_ZTIP6Opaque"
+    },
+    {
+     "referenced_type" : "_ZTIP18DefinedInOneHeader"
+    }
+   ],
+   "return_type" : "_ZTIv",
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "function_name" : "func2",
+   "linker_set_key" : "func2",
+   "parameters" :
+   [
+    {
+     "referenced_type" : "_ZTIP18DefinedInOneHeader#ODR:/link_to_def2.h.sdump"
+    }
+   ],
+   "return_type" : "_ZTIv",
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h"
+  }
+ ],
+ "global_vars" :
+ [
+  {
+   "linker_set_key" : "var",
+   "name" : "var",
+   "referenced_type" : "_ZTIc",
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  }
+ ],
+ "lvalue_reference_types" : [],
+ "pointer_types" :
+ [
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP18DefinedInOneHeader",
+   "name" : "DefinedInOneHeader *",
+   "referenced_type" : "_ZTI18DefinedInOneHeader",
+   "self_type" : "_ZTIP18DefinedInOneHeader",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP6Opaque",
+   "name" : "Opaque *",
+   "referenced_type" : "_ZTI6Opaque",
+   "self_type" : "_ZTIP6Opaque",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP6Struct",
+   "name" : "Struct *",
+   "referenced_type" : "_ZTI6Struct",
+   "self_type" : "_ZTIP6Struct",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP6Struct",
+   "name" : "Struct *",
+   "referenced_type" : "_ZTI6Struct#ODR:/link_to_def2.h.sdump",
+   "self_type" : "_ZTIP6Struct#ODR:/link_to_def2.h.sdump",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h"
+  }
+ ],
+ "qualified_types" : [],
+ "record_types" :
+ [
+  {
+   "alignment" : 1,
+   "linker_set_key" : "_ZTI18DefinedInOneHeader",
+   "name" : "DefinedInOneHeader",
+   "referenced_type" : "_ZTI18DefinedInOneHeader",
+   "self_type" : "_ZTI18DefinedInOneHeader",
+   "size" : 1,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h"
+  },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member1",
+     "referenced_type" : "_ZTIP6Struct"
+    }
+   ],
+   "linker_set_key" : "_ZTI6Struct",
+   "name" : "Struct",
+   "referenced_type" : "_ZTI6Struct",
+   "self_type" : "_ZTI6Struct",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "alignment" : 8,
+   "fields" :
+   [
+    {
+     "field_name" : "member2",
+     "referenced_type" : "_ZTIP6Struct#ODR:/link_to_def2.h.sdump"
+    }
+   ],
+   "linker_set_key" : "_ZTI6Struct",
+   "name" : "Struct",
+   "referenced_type" : "_ZTI6Struct#ODR:/link_to_def2.h.sdump",
+   "self_type" : "_ZTI6Struct#ODR:/link_to_def2.h.sdump",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/link_to_def2.h"
+  }
+ ],
+ "rvalue_reference_types" : []
+}
diff --git a/vndk/tools/header-checker/tests/reference_dumps/arm64/libmerge_multi_definitions.so.lsdump b/vndk/tools/header-checker/tests/reference_dumps/arm64/libmerge_multi_definitions.so.lsdump
index ab6a33965..1c425d715 100644
--- a/vndk/tools/header-checker/tests/reference_dumps/arm64/libmerge_multi_definitions.so.lsdump
+++ b/vndk/tools/header-checker/tests/reference_dumps/arm64/libmerge_multi_definitions.so.lsdump
@@ -33,6 +33,9 @@
   {
    "name" : "func"
   },
+  {
+   "name" : "func2"
+  },
   {
    "name" : "var"
   }
@@ -40,7 +43,39 @@
  "elf_objects" : [],
  "enum_types" : [],
  "function_types" : [],
- "functions" : [],
+ "functions" :
+ [
+  {
+   "function_name" : "func",
+   "linker_set_key" : "func",
+   "parameters" :
+   [
+    {
+     "referenced_type" : "_ZTIP6Struct"
+    },
+    {
+     "referenced_type" : "_ZTIP6Opaque"
+    },
+    {
+     "referenced_type" : "_ZTIP18DefinedInOneHeader"
+    }
+   ],
+   "return_type" : "_ZTIv",
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "function_name" : "func2",
+   "linker_set_key" : "func2",
+   "parameters" :
+   [
+    {
+     "referenced_type" : "_ZTIP18DefinedInOneHeader#ODR:/def2.h.sdump"
+    }
+   ],
+   "return_type" : "_ZTIv",
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h"
+  }
+ ],
  "global_vars" :
  [
   {
@@ -53,6 +88,24 @@
  "lvalue_reference_types" : [],
  "pointer_types" :
  [
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP18DefinedInOneHeader",
+   "name" : "DefinedInOneHeader *",
+   "referenced_type" : "_ZTI18DefinedInOneHeader",
+   "self_type" : "_ZTIP18DefinedInOneHeader",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
+  {
+   "alignment" : 8,
+   "linker_set_key" : "_ZTIP6Opaque",
+   "name" : "Opaque *",
+   "referenced_type" : "_ZTI6Opaque",
+   "self_type" : "_ZTIP6Opaque",
+   "size" : 8,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
+  },
   {
    "alignment" : 8,
    "linker_set_key" : "_ZTIP6Struct",
@@ -70,68 +123,20 @@
    "self_type" : "_ZTIP6Struct#ODR:/def2.h.sdump",
    "size" : 8,
    "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h"
-  },
-  {
-   "alignment" : 8,
-   "linker_set_key" : "_ZTIPK6Opaque",
-   "name" : "const Opaque *",
-   "referenced_type" : "_ZTIK6Opaque",
-   "self_type" : "_ZTIPK6Opaque",
-   "size" : 8,
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
-  },
-  {
-   "alignment" : 8,
-   "linker_set_key" : "_ZTIPK6Struct",
-   "name" : "const Struct *",
-   "referenced_type" : "_ZTIK6Struct",
-   "self_type" : "_ZTIPK6Struct",
-   "size" : 8,
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
-  },
-  {
-   "alignment" : 8,
-   "linker_set_key" : "_ZTIPK6Struct",
-   "name" : "const Struct *",
-   "referenced_type" : "_ZTIK6Struct#ODR:/def2.h.sdump",
-   "self_type" : "_ZTIPK6Struct#ODR:/def2.h.sdump",
-   "size" : 8,
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h"
-  }
- ],
- "qualified_types" :
- [
-  {
-   "is_const" : true,
-   "linker_set_key" : "_ZTIK6Opaque",
-   "name" : "const Opaque",
-   "referenced_type" : "_ZTI6Opaque",
-   "self_type" : "_ZTIK6Opaque",
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
-  },
-  {
-   "alignment" : 8,
-   "is_const" : true,
-   "linker_set_key" : "_ZTIK6Struct",
-   "name" : "const Struct",
-   "referenced_type" : "_ZTI6Struct#ODR:/def2.h.sdump",
-   "self_type" : "_ZTIK6Struct#ODR:/def2.h.sdump",
-   "size" : 8,
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h"
-  },
-  {
-   "alignment" : 8,
-   "is_const" : true,
-   "linker_set_key" : "_ZTIK6Struct",
-   "name" : "const Struct",
-   "referenced_type" : "_ZTI6Struct",
-   "self_type" : "_ZTIK6Struct",
-   "size" : 8,
-   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def1.h"
   }
  ],
+ "qualified_types" : [],
  "record_types" :
  [
+  {
+   "alignment" : 1,
+   "linker_set_key" : "_ZTI18DefinedInOneHeader",
+   "name" : "DefinedInOneHeader",
+   "referenced_type" : "_ZTI18DefinedInOneHeader",
+   "self_type" : "_ZTI18DefinedInOneHeader",
+   "size" : 1,
+   "source_file" : "development/vndk/tools/header-checker/tests/integration/merge_multi_definitions/include/def2.h"
+  },
   {
    "alignment" : 8,
    "fields" :
diff --git a/vndk/tools/header-checker/tests/test.py b/vndk/tools/header-checker/tests/test.py
index e33ff97c4..7c0f43c7f 100755
--- a/vndk/tools/header-checker/tests/test.py
+++ b/vndk/tools/header-checker/tests/test.py
@@ -387,6 +387,11 @@ class HeaderCheckerTest(unittest.TestCase):
     def test_merge_multi_definitions(self):
         self.prepare_and_absolute_diff_all_archs(
             "libmerge_multi_definitions", "libmerge_multi_definitions")
+        self.prepare_and_run_abi_diff_all_archs(
+            "libmerge_multi_definitions", "libdiff_multi_definitions", 0,
+            flags=["-input-format-new", "Json", "-input-format-old", "Json",
+                   "-consider-opaque-types-different"],
+            create_old=False, create_new=False)
 
     def test_print_resource_dir(self):
         dumper_path = shutil.which("header-abi-dumper")