diff --git a/hw/misc/avr_power.c b/hw/misc/avr_power.c
index f42cf4fd90..42be265691 100644
--- a/hw/misc/avr_power.c
+++ b/hw/misc/avr_power.c
@@ -73,6 +73,9 @@ static const MemoryRegionOps avr_mask_ops = {
     .impl = {
         .max_access_size = 1,
     },
+    .valid = {
+        .max_access_size = 1,
+    },
 };
 
 static void avr_mask_init(Object *dev)