diff --git a/ophyd/_pyepics_shim.py b/ophyd/_pyepics_shim.py
index 118ee20d8..09c83ea5f 100644
--- a/ophyd/_pyepics_shim.py
+++ b/ophyd/_pyepics_shim.py
@@ -7,6 +7,10 @@
 
 from ._dispatch import EventDispatcher, _CallbackThread, wrap_callback
 
+# suspect attempt to monkey-patch printf is causing segfaults
+if hasattr(ca, "WITH_CA_MESSAGES"):
+    ca.WITH_CA_MESSAGES = True
+
 _min_pyepics = "3.4.2"
 
 if parse(epics.__version__) < parse(_min_pyepics):
diff --git a/ophyd/device.py b/ophyd/device.py
index 270e19759..59f579ccb 100644
--- a/ophyd/device.py
+++ b/ophyd/device.py
@@ -234,7 +234,7 @@ def maybe_add_prefix(self, instance, kw, suffix):
             suffix from.
 
         kw : str
-            The key of associated with the suffix.  If this key is
+            The key of associated with the suffix.  If this key is in
             self.add_prefix than prepend the prefix to the suffix and
             return, else just return the suffix.
 
@@ -253,10 +253,12 @@ def create_component(self, instance):
         "Instantiate the object described by this Component for a Device"
         kwargs = self.kwargs.copy()
         kwargs.update(
-            name=f"{instance.name}_{self.attr}",
+            name=f"{instance.name}{instance._child_name_separator}{self.attr}",
             kind=instance._component_kinds[self.attr],
             attr_name=self.attr,
         )
+        if issubclass(self.cls, Device):
+            kwargs.setdefault("child_name_separator", instance._child_name_separator)
 
         for kw, val in list(kwargs.items()):
             kwargs[kw] = self.maybe_add_prefix(instance, kw, val)
@@ -839,10 +841,11 @@ def __init__(
         read_attrs=None,
         configuration_attrs=None,
         parent=None,
+        child_name_separator="_",
         **kwargs,
     ):
         self._destroyed = False
-
+        self._child_name_separator = child_name_separator
         # Store EpicsSignal objects (only created once they are accessed)
         self._signals = {}
 
diff --git a/ophyd/tests/test_device.py b/ophyd/tests/test_device.py
index 926bbab53..0aec7bca3 100644
--- a/ophyd/tests/test_device.py
+++ b/ophyd/tests/test_device.py
@@ -969,3 +969,31 @@ class FakeTriggerableDevice(Device):
 
     d.trigger()
     assert d.strigger.get() == after
+
+
+def test_child_separator():
+    class Test(Device):
+        a = Component(Signal)
+        b = Component(Signal)
+
+    t = Test(name="bob")
+    assert t.a.name == "bob_a"
+
+    t = Test(name="bob", child_name_separator="-")
+    assert t.a.name == "bob-a"
+
+    class Test2(Device):
+        c = Component(Signal)
+        d = Component(Signal)
+        t = Component(Test)
+        s = Component(Test, child_name_separator="?")
+
+    t2 = Test2(name="bob", child_name_separator="!")
+
+    assert t2.c.name == "bob!c"
+    assert t2.d.name == "bob!d"
+
+    assert t2.t.a.name == "bob!t!a"
+    assert t2.t.b.name == "bob!t!b"
+    assert t2.s.a.name == "bob!s?a"
+    assert t2.s.b.name == "bob!s?b"
diff --git a/setup.cfg b/setup.cfg
index bf835213f..6db9029ac 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -50,7 +50,7 @@ dev =
     numpydoc
     pre-commit
     pydata-sphinx-theme
-    pyepics>=3.4.2
+    pyepics>=3.4.2,<3.5.7
     pytest
     pytest-asyncio
     pytest-cov