diff --git a/sim/mcuboot-sys/src/api.rs b/sim/mcuboot-sys/src/api.rs
index 0a098ff..56c685c 100644
--- a/sim/mcuboot-sys/src/api.rs
+++ b/sim/mcuboot-sys/src/api.rs
@@ -388,3 +388,13 @@
     });
     return rc;
 }
+
+pub fn sim_reset_nv_counters() {
+    NV_COUNTER_CTX.with(|ctx| {
+        let mut counter_storage = ctx.borrow_mut();
+
+        for i in 0..counter_storage.storage.len() {
+            counter_storage.storage[i] = 0;
+        }
+    });
+}
diff --git a/sim/mcuboot-sys/src/c.rs b/sim/mcuboot-sys/src/c.rs
index 9d2a321..2643866 100644
--- a/sim/mcuboot-sys/src/c.rs
+++ b/sim/mcuboot-sys/src/c.rs
@@ -166,6 +166,10 @@
     return counter_val;
 }
 
+pub fn reset_security_counters() {
+    api::sim_reset_nv_counters();
+}
+
 mod raw {
     use crate::area::CAreaDesc;
     use crate::api::{BootRsp, CSimContext};
diff --git a/sim/src/image.rs b/sim/src/image.rs
index a8f3604..14e59d6 100644
--- a/sim/src/image.rs
+++ b/sim/src/image.rs
@@ -239,7 +239,7 @@
                 let upgr   = match deps.depends[image_num] {
                     DepType::NoUpgrade => install_no_image(),
                     _ => install_image(&mut flash, &self.areadesc, &slots, 1,
-                        maximal(46928), &ram, &*dep, ImageManipulation::BadSignature, Some(0))
+                        maximal(46928), &ram, &*dep, ImageManipulation::BadSignature, Some(1))
                 };
                 (prim, upgr)
             } else {
@@ -248,7 +248,7 @@
                 let upgr = match deps.depends[image_num] {
                         DepType::NoUpgrade => install_no_image(),
                         _ => install_image(&mut flash, &self.areadesc, &slots, 1,
-                            maximal(46928), &ram, &*dep, img_manipulation, Some(0))
+                            maximal(46928), &ram, &*dep, img_manipulation, Some(1))
                     };
                 (prim, upgr)
             };
@@ -289,6 +289,10 @@
                 }
         };
 
+        // As a side effect, the upgrade performed above has updated the security counters. Reset
+        // them to their original value.
+        c::reset_security_counters();
+
         images.total_count = Some(total_count);
         images
     }
diff --git a/sim/tests/core.rs b/sim/tests/core.rs
index c246aa8..0e7687a 100644
--- a/sim/tests/core.rs
+++ b/sim/tests/core.rs
@@ -21,6 +21,7 @@
     env,
     sync::atomic::{AtomicUsize, Ordering},
 };
+use mcuboot_sys::c;
 
 /// A single test, after setting up logging and such.  Within the $body,
 /// $arg will be bound to each device.
@@ -90,6 +91,7 @@
         let image = r.clone().make_image(&dep, true);
         dump_image(&image, "dependency_combos");
         assert!(!image.run_check_deps(&dep));
+        c::reset_security_counters();
     }
 });