diff --git a/sim/mcuboot-sys/src/area.rs b/sim/mcuboot-sys/src/area.rs
index 95eea41..1ebb405 100644
--- a/sim/mcuboot-sys/src/area.rs
+++ b/sim/mcuboot-sys/src/area.rs
@@ -9,6 +9,7 @@
 use simflash::{Flash, SimFlash, Sector};
 use std::ptr;
 use std::collections::HashMap;
+use std::borrow::BorrowMut;
 
 /// Structure to build up the boot area table.
 #[derive(Debug, Default, Clone)]
@@ -124,8 +125,9 @@
         None
     }
 
-    pub fn get_c(&self) -> CAreaDesc {
-        let mut areas: CAreaDesc = Default::default();
+    pub fn get_c(&self) -> Box<CAreaDesc> {
+        let mut areas_box: Box<CAreaDesc> = Box::new(Default::default());
+        let areas: &mut CAreaDesc = areas_box.borrow_mut();
 
         assert_eq!(self.areas.len(), self.whole.len());
 
@@ -140,7 +142,7 @@
 
         areas.num_slots = self.areas.len() as u32;
 
-        areas
+        areas_box
     }
 
     /// Return an iterator over all `FlashArea`s present.
diff --git a/sim/mcuboot-sys/src/c.rs b/sim/mcuboot-sys/src/c.rs
index 483ca8f..284cac0 100644
--- a/sim/mcuboot-sys/src/c.rs
+++ b/sim/mcuboot-sys/src/c.rs
@@ -13,6 +13,8 @@
 #[allow(unused)]
 use std::sync::Once;
 
+use std::borrow::Borrow;
+
 /// The result of an invocation of `boot_go`.  This is intentionally opaque so that we can provide
 /// accessors for everything we need from this.
 #[derive(Debug)]
@@ -90,12 +92,13 @@
         image_off: 0,
     };
     let result: i32 = unsafe {
+        let adesc = areadesc.get_c();
         match image_index {
             None => raw::invoke_boot_go(&mut sim_ctx as *mut _,
-                                        &areadesc.get_c() as *const _,
+                                        adesc.borrow() as *const _,
                                         &mut rsp as *mut _, -1) as i32,
             Some(i) => raw::invoke_boot_go(&mut sim_ctx as *mut _,
-                                           &areadesc.get_c() as *const _,
+                                           adesc.borrow() as *const _,
                                            &mut rsp as *mut _,
                                            i as i32) as i32
         }