diff --git a/reticulum-daemon/reticulum_daemon.py b/reticulum-daemon/reticulum_daemon.py
index 2fd17985..3fb15eef 100644
--- a/reticulum-daemon/reticulum_daemon.py
+++ b/reticulum-daemon/reticulum_daemon.py
@@ -502,7 +502,32 @@ def _parse_args(argv):
     return p.parse_args(argv)
 
 
+def _install_parent_death_signal() -> None:
+    """Die when our parent process does.
+
+    The daemon ships as a PyInstaller one-file binary: our direct parent is the
+    bootloader, and the Rust supervisor (mesh/reticulum.rs) stops us by SIGKILL-
+    ing that bootloader. SIGKILL can't be forwarded, so without this the Python
+    child is orphaned and keeps holding the RNode serial port — which piles up
+    stale daemons that jam the radio (observed: 9 instances on one node). Asking
+    the kernel to send us SIGTERM on parent death lets our existing SIGTERM
+    handler shut down cleanly and free the port. Linux-only; no-op elsewhere.
+    """
+    if sys.platform != "linux":
+        return
+    try:
+        import ctypes
+
+        PR_SET_PDEATHSIG = 1
+        ctypes.CDLL("libc.so.6", use_errno=True).prctl(
+            PR_SET_PDEATHSIG, signal.SIGTERM
+        )
+    except Exception:
+        pass  # best-effort; never block startup on this
+
+
 def main(argv=None) -> int:
+    _install_parent_death_signal()
     args = _parse_args(argv if argv is not None else sys.argv[1:])
 
     if args.check: