diff --git a/cuda_bindings_12/cuda/bindings/_internal/utils.pyx b/cuda_bindings_12/cuda/bindings/_internal/utils.pyx
index df17a9e47df..ce9012113df 100644
--- a/cuda_bindings_12/cuda/bindings/_internal/utils.pyx
+++ b/cuda_bindings_12/cuda/bindings/_internal/utils.pyx
@@ -98,7 +98,14 @@ cdef int get_nested_resource_ptr(nested_resource[ResT] &in_out_ptr, object obj,
         nested_ptr.reset(nested_vec, True)
         for i, obj_i in enumerate(obj):
             if ResT is char:
-                obj_i_bytes = (<str?>(obj_i)).encode()
+                obj_i_type = type(obj_i)
+                if obj_i_type is str:
+                    obj_i_bytes = obj_i.encode("utf-8")
+                elif obj_i_type is bytes:
+                    obj_i_bytes = obj_i
+                else:
+                    raise TypeError(
+                        f"Expected str or bytes, got {obj_i_type.__name__}")
                 str_len = <size_t>(len(obj_i_bytes)) + 1  # including null termination
                 deref(nested_res_vec)[i].resize(str_len)
                 obj_i_ptr = <char*>(obj_i_bytes)
diff --git a/cuda_bindings_12/cuda/bindings/_lib/utils.pxd b/cuda_bindings_12/cuda/bindings/_lib/utils.pxd
index 706c6d3fc7a..c36ddfb0d12 100644
--- a/cuda_bindings_12/cuda/bindings/_lib/utils.pxd
+++ b/cuda_bindings_12/cuda/bindings/_lib/utils.pxd
@@ -152,6 +152,7 @@ cdef class _HelperCUcoredumpSettings:
     cdef cydriver.CUcoredumpSettings_enum _attrib
     cdef bint _is_getter
     cdef size_t _size
+    cdef object _references  # keeps caller bytes alive so _charstar stays valid
 
     # Return values
     cdef cpp_bool _bool
diff --git a/cuda_bindings_12/cuda/bindings/_lib/utils.pxi b/cuda_bindings_12/cuda/bindings/_lib/utils.pxi
index c11d0d0c197..eebdd17b41e 100644
--- a/cuda_bindings_12/cuda/bindings/_lib/utils.pxi
+++ b/cuda_bindings_12/cuda/bindings/_lib/utils.pxi
@@ -734,6 +734,8 @@ cdef class _HelperCUcoredumpSettings:
                 self._cptr = <void*><void_ptr>self._charstar
                 self._size = 1024
             else:
+                # Keep a reference so the borrowed _charstar buffer stays alive.
+                self._references = init_value
                 self._charstar = init_value
                 self._cptr = <void*><void_ptr>self._charstar
                 self._size = len(init_value)
@@ -756,7 +758,9 @@ cdef class _HelperCUcoredumpSettings:
             raise TypeError('Unsupported attribute: {}'.format(attr.name))
 
     def __dealloc__(self):
-        pass
+        # Only the getter owns heap storage; the setter borrows caller bytes.
+        if self._is_getter:
+            free(self._charstar)
 
     @property
     def cptr(self):
diff --git a/cuda_bindings_12/cuda/bindings/utils/__init__.py b/cuda_bindings_12/cuda/bindings/utils/__init__.py
index 62d083dc7c6..d6136da14b0 100644
--- a/cuda_bindings_12/cuda/bindings/utils/__init__.py
+++ b/cuda_bindings_12/cuda/bindings/utils/__init__.py
@@ -26,6 +26,9 @@ def get_cuda_native_handle(obj: Any) -> int:
     """
     obj_type = type(obj)
     try:
-        return _handle_getters[obj_type](obj)
+        getter = _handle_getters[obj_type]
     except KeyError:
         raise TypeError("Unknown type: " + str(obj_type)) from None
+    # Deliberately outside the try: a KeyError raised by the getter itself is a
+    # bug in that getter, not an unregistered type.
+    return getter(obj)
diff --git a/cuda_bindings_12/tests/test_nvjitlink.py b/cuda_bindings_12/tests/test_nvjitlink.py
index 19dc040e47d..bec58b7a048 100644
--- a/cuda_bindings_12/tests/test_nvjitlink.py
+++ b/cuda_bindings_12/tests/test_nvjitlink.py
@@ -100,6 +100,13 @@ def test_create_and_destroy(option):
     nvjitlink.destroy(handle)
 
 
+@pytest.mark.human_authored
+def test_create_and_destroy_bytes_options():
+    handle = nvjitlink.create(1, [b"-arch=sm_80"])
+    assert handle != 0
+    nvjitlink.destroy(handle)
+
+
 @pytest.mark.parametrize("option", ARCHITECTURES)
 def test_complete_empty(option):
     handle = nvjitlink.create(1, [f"-arch={option}"])
diff --git a/cuda_bindings_12/tests/test_nvvm.py b/cuda_bindings_12/tests/test_nvvm.py
index bd6f49f03f1..3cea5a0f817 100644
--- a/cuda_bindings_12/tests/test_nvvm.py
+++ b/cuda_bindings_12/tests/test_nvvm.py
@@ -246,7 +246,7 @@ def test_get_buffer_empty(get_size, get_buffer):
         assert buffer == b"\x00"
 
 
-@pytest.mark.parametrize("options", [[], ["-opt=0"], ["-opt=3", "-g"]])
+@pytest.mark.parametrize("options", [[], ["-opt=0"], ["-opt=3", "-g"], [b"-opt=0"]])
 def test_compile_program_with_minimal_nvvm_ir(minimal_nvvmir, options):
     with nvvm_program() as prog:
         nvvm.add_module_to_program(prog, minimal_nvvmir, len(minimal_nvvmir), "FileNameHere.ll")
diff --git a/cuda_bindings_12/tests/test_utils.py b/cuda_bindings_12/tests/test_utils.py
index 8904d65d2ed..33487c7f529 100644
--- a/cuda_bindings_12/tests/test_utils.py
+++ b/cuda_bindings_12/tests/test_utils.py
@@ -92,6 +92,27 @@ def test_get_handle_error(target):
         handle = get_cuda_native_handle(target)
 
 
+@pytest.mark.agent_authored(model="claude-opus-5")
+def test_get_handle_does_not_report_a_registered_type_as_unknown(monkeypatch):
+    """A KeyError from inside a handle getter is a bug in that getter.
+
+    Reporting it as "Unknown type" is wrong twice over: the type *is*
+    registered, and `from None` hides the traceback that would say otherwise.
+    """
+    from cuda.bindings.utils import _handle_getters
+
+    class Registered:
+        pass
+
+    def getter(_obj):
+        raise KeyError("lookup inside the getter failed")
+
+    monkeypatch.setitem(_handle_getters, Registered, getter)
+
+    with pytest.raises(KeyError, match="lookup inside the getter failed"):
+        get_cuda_native_handle(Registered())
+
+
 @pytest.mark.parametrize(
     "module",
     [