diff --git a/src/copapy/stencil_db.py b/src/copapy/stencil_db.py
index febda61..c060354 100644
--- a/src/copapy/stencil_db.py
+++ b/src/copapy/stencil_db.py
@@ -1,5 +1,5 @@
 from dataclasses import dataclass
-import pelfy
+from pelfy import open_elf_file, elf_file, elf_symbol
 from typing import Generator, Literal
 from enum import Enum
 
@@ -42,7 +42,7 @@ def translate_relocation(relocation_addr: int, reloc_type: str, bits: int, r_add
         raise Exception(f"Unknown relocation type: {reloc_type}")
 
 
-def get_return_function_type(symbol: pelfy.elf_symbol) -> str:
+def get_return_function_type(symbol: elf_symbol) -> str:
     if symbol.relocations:
         result_func = symbol.relocations[-1].symbol
         if result_func.name.startswith('result_'):
@@ -50,20 +50,41 @@ def get_return_function_type(symbol: pelfy.elf_symbol) -> str:
     return 'void'
 
 
-def strip_symbol(data: bytes, byteorder: ByteOrder) -> bytes:
+def strip_function(func: elf_symbol) -> bytes:
     """Return striped function code based on NOP markers"""
-    start_index, end_index = get_stencil_position(data, byteorder)
-    return data[start_index:end_index]
+    start_index, end_index = get_stencil_position(func)
+    return func.data[start_index:end_index]
 
 
-def get_stencil_position(data: bytes, byteorder: ByteOrder) -> tuple[int, int]:
+def get_stencil_position(func: elf_symbol) -> tuple[int, int]:
+
+    #assert func.name != 'function_start', func.relocations
+
     # Find first start marker
-    marker_index = data.find(START_MARKER.to_bytes(MARKER_LENGTH, byteorder))
+    marker_index = func.data.find(START_MARKER.to_bytes(MARKER_LENGTH, func.file.byteorder))
     start_index = 0 if marker_index < 0 else marker_index + MARKER_LENGTH
 
     # Find last end marker
-    end_index = data.rfind(END_MARKER.to_bytes(MARKER_LENGTH, byteorder))
-    end_index = len(data) if end_index < 0 else end_index - LENGTH_CALL_INSTRUCTION
+    end_index = func.data.rfind(END_MARKER.to_bytes(MARKER_LENGTH, func.file.byteorder))
+    end_index = len(func.data) if end_index < 0 else end_index - LENGTH_CALL_INSTRUCTION
+
+    reloc = func.relocations[-1]
+    end_index2 = reloc.fields['r_offset'] - func.fields['st_value'] - reloc.fields['r_addend'] - LENGTH_CALL_INSTRUCTION
+
+    print(func.relocations[-1])
+    assert end_index2 == end_index, func.name
+
+    return start_index, end_index
+
+
+def get_stencil_position2(func: elf_symbol) -> tuple[int, int]:
+    # Find first start marker
+    marker_index = func.data.find(START_MARKER.to_bytes(MARKER_LENGTH, func.file.byteorder))
+    start_index = 0 if marker_index < 0 else marker_index + MARKER_LENGTH
+
+    # Find last end marker
+    end_index = func.data.rfind(END_MARKER.to_bytes(MARKER_LENGTH, func.file.byteorder))
+    end_index = len(func.data) if end_index < 0 else end_index - LENGTH_CALL_INSTRUCTION
 
     return start_index, end_index
 
@@ -86,20 +107,20 @@ class stencil_database():
             obj_file: path to the ELF object file or bytes of the ELF object file
         """
         if isinstance(obj_file, str):
-            self.elf = pelfy.open_elf_file(obj_file)
+            self.elf = open_elf_file(obj_file)
         else:
-            self.elf = pelfy.elf_file(obj_file)
+            self.elf = elf_file(obj_file)
 
         self.function_definitions = {s.name: get_return_function_type(s)
                                      for s in self.elf.symbols
                                      if s.info == 'STT_FUNC'}
-        self.data = {s.name: strip_symbol(s.data, self.elf.byteorder)
+        self.data = {s.name: strip_function(s)
                      for s in self.elf.symbols
                      if s.info == 'STT_FUNC'}
         self.var_size = {s.name: s.fields['st_size']
                          for s in self.elf.symbols
                          if s.info == 'STT_OBJECT'}
-        self.byteorder = self.elf.byteorder
+        self.byteorder: ByteOrder = self.elf.byteorder
 
         for name in self.function_definitions.keys():
             sym = self.elf.symbols[name]
@@ -116,7 +137,7 @@ class stencil_database():
             patch_entry: every relocation for the symbol
         """
         symbol = self.elf.symbols[symbol_name]
-        start_index, end_index = get_stencil_position(symbol.data, symbol.file.byteorder)
+        start_index, end_index = get_stencil_position(symbol)
 
         for reloc in symbol.relocations:
 
@@ -140,4 +161,4 @@ class stencil_database():
         Returns:
             Striped function code
         """
-        return strip_symbol(self.elf.symbols[name].data, self.elf.byteorder)
+        return strip_function(self.elf.symbols[name])
diff --git a/tests/test_stencil_db.py b/tests/test_stencil_db.py
index 5f92064..ab7b4b7 100644
--- a/tests/test_stencil_db.py
+++ b/tests/test_stencil_db.py
@@ -16,12 +16,12 @@ def test_start_end_function():
     arch = platform.machine()
     sdb = stencil_database(f'src/copapy/obj/stencils_{arch}_O3.o')
     for sym_name in sdb.function_definitions.keys():
-        data = sdb.elf.symbols[sym_name].data
-        print('-', sym_name, stencil_db.get_stencil_position(data, sdb.elf.byteorder), len(data))
+        symbol = sdb.elf.symbols[sym_name]
+        print('-', sym_name, stencil_db.get_stencil_position(symbol), len(symbol.data))
 
-        start, end = stencil_db.get_stencil_position(data, sdb.elf.byteorder)
+        start, end = stencil_db.get_stencil_position(symbol)
 
-        assert start >= 0 and end >= start and end <= len(data)
+        assert start >= 0 and end >= start and end <= len(symbol.data)
 
 
 if __name__ == "__main__":