diff --git a/pyproject.toml b/pyproject.toml
index 70869d65d..f01766273 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,7 +65,7 @@ dev = [
     "click>=7.0,<8.2",
     "hypothesis>=5.8,<7",
     "pdoc>=4.0.0",
-    "pyinstaller==6.1.0",
+    "pyinstaller==6.2.0",
     "pytest-asyncio>=0.17,<0.22",
     "pytest-cov>=2.7.1,<4.2",
     "pytest-timeout>=1.3.3,<2.3",
diff --git a/release/specs/mitmdump b/release/specs/mitmdump
index 0aeac3c84..d5f4e859e 100644
--- a/release/specs/mitmdump
+++ b/release/specs/mitmdump
@@ -1,3 +1,17 @@
 #!/usr/bin/env python
+import faulthandler
+import signal
+faulthandler.enable()
+faulthandler.register(signal.SIGUSR1.value)
+
+from OpenSSL._util import ffi
+print("creating callback")
+ffi.callback(
+	"int (*)(SSL *, unsigned char **, unsigned char *, "
+	"const unsigned char *, unsigned int, void *)",
+	lambda *_, **__: None
+)
+print("ok")
+
 from mitmproxy.tools.main import mitmdump
 mitmdump()