diff --git a/src/mame/drivers/hp80.cpp b/src/mame/drivers/hp80.cpp
index 64c7d3d5d4d..ea97ae42c3c 100644
--- a/src/mame/drivers/hp80.cpp
+++ b/src/mame/drivers/hp80.cpp
@@ -328,7 +328,8 @@ static const uint8_t vector_table[] = {
 	0x10,   // Slot 1
 	0x10,   // Slot 2
 	0x10,   // Slot 3
-	0x10    // Slot 4
+	0x10,   // Slot 4
+	0x00    // No IRQ
 };
 
 IRQ_CALLBACK_MEMBER(hp85_state::irq_callback)