diff --git a/artiq/coredevice/exceptions.py b/artiq/coredevice/exceptions.py
index 3ec699b07..cf48a3281 100644
--- a/artiq/coredevice/exceptions.py
+++ b/artiq/coredevice/exceptions.py
@@ -174,3 +174,7 @@ class I2CError(Exception):
 class SPIError(Exception):
     """Raised when a SPI transaction fails."""
     artiq_builtin = True
+
+class UnwrapNoneError(Exception):
+    """Raised when unwrapping a none Option."""
+    artiq_builtin = True