diff --git a/Cargo.toml b/Cargo.toml
index 1270ab7..ca9bba2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,6 +28,7 @@ trussed-staging = { version = "0.1.0", default-features = false, optional = true
 apdu-dispatch = { version = "0.1", optional = true }
 ctaphid-dispatch = { version = "0.1", optional = true }
 iso7816 = { version = "0.1", optional = true }
+serde-byte-array = "0.1.2"
 
 [features]
 dispatch = ["apdu-dispatch", "ctaphid-dispatch", "iso7816"]
@@ -46,6 +47,7 @@ log-error = []
 
 [dev-dependencies]
 env_logger = "0.11.0"
+hex-literal = "0.4.1"
 # quickcheck = "1"
 rand = "0.8.4"
 trussed = { version = "0.1", features = ["virt"] }
@@ -56,6 +58,7 @@ usbd-ctaphid = "0.1.0"
 features = ["dispatch"]
 
 [patch.crates-io]
+cbor-smol = { git = "https://github.com/sosthene-nitrokey/cbor-smol.git", rev = "94ee8c28edf9248b402aa4335c1dee157995197b"}
 ctap-types = { git = "https://github.com/trussed-dev/ctap-types.git", rev = "7d4ad69e64ad308944c012aef5b9cfd7654d9be8" }
 ctaphid-dispatch = { git = "https://github.com/trussed-dev/ctaphid-dispatch.git", rev = "57cb3317878a8593847595319aa03ef17c29ec5b" }
 apdu-dispatch = { git = "https://github.com/trussed-dev/apdu-dispatch.git", rev = "915fc237103fcecc29d0f0b73391f19abf6576de" }
@@ -64,3 +67,4 @@ trussed-staging = { git = "https://github.com/trussed-dev/trussed-staging", rev
 serde-indexed = { git = "https://github.com/sosthene-nitrokey/serde-indexed.git", rev = "5005d23cb4ee8622e62188ea0f9466146f851f0d" }
 trussed-usbip = { git = "https://github.com/Nitrokey/pc-usbip-runner.git", tag = "v0.0.1-nitrokey.1" }
 usbd-ctaphid = { git = "https://github.com/Nitrokey/usbd-ctaphid.git", tag = "v0.1.0-nitrokey.2" }
+cbor-smol = { path = "../cbor-smol" }
diff --git a/src/state.rs b/src/state.rs
index 7b524aa..af05287 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -263,6 +263,7 @@ pub struct PersistentState {
     key_encryption_key: Option<KeyId>,
     key_wrapping_key: Option<KeyId>,
     consecutive_pin_mismatches: u8,
+    #[serde(with = "serde_byte_array")]
     pin_hash: Option<[u8; 16]>,
     // Ideally, we'd dogfood a "Monotonic Counter" from trussed.
     // TODO: Add per-key counters for resident keys.
@@ -592,3 +593,23 @@ impl RuntimeState {
         Ok(shared_secret)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use hex_literal::hex;
+
+    #[test]
+    fn deser() {
+        let _state: PersistentState = trussed::cbor_deserialize(&hex!(
+            "
+            a5726b65795f656e6372797074696f6e5f6b657950b19a5a2845e5ec71e3
+            2a1b890892376c706b65795f7772617070696e675f6b6579f6781a636f6e
+            73656375746976655f70696e5f6d69736d617463686573006870696e5f68
+            6173689018ef1879187c1881181818f0182d18fb186418960718dd185d18
+            3f188c18766974696d657374616d7009
+        "
+        ))
+        .unwrap();
+    }
+}