diff --git a/Cargo-recent.lock b/Cargo-recent.lock
index c56d0661..c1933b9e 100644
--- a/Cargo-recent.lock
+++ b/Cargo-recent.lock
@@ -503,7 +503,7 @@ dependencies = [
  "miniscript",
  "santiago",
  "serde",
- "simplicity-sys 0.6.1",
+ "simplicity-sys 0.6.2",
 ]
 
 [[package]]
@@ -518,7 +518,7 @@ dependencies = [
 
 [[package]]
 name = "simplicity-sys"
-version = "0.6.1"
+version = "0.6.2"
 dependencies = [
  "bitcoin_hashes",
  "cc",
diff --git a/Cargo.toml b/Cargo.toml
index 076b1f9a..f8e4e15c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,14 +30,14 @@ ghost-cell = { version = "0.2.6", default-features = false }
 hashes = { package = "bitcoin_hashes", version = "0.14" }
 hex = { package = "hex-conservative", version = "0.2.1" }
 santiago = "1.3"
-simplicity-sys = { version = "0.6.1", path = "./simplicity-sys" }
+simplicity-sys = { version = "0.6.2", path = "./simplicity-sys" }
 serde = { version = "1.0.103", features = ["derive"], optional = true }
 
 [target.wasm32-unknown-unknown.dependencies]
 getrandom = { version = "0.2", features = ["js"] }
 
 [dev-dependencies]
-simplicity-sys = { version = "0.6.1", path = "./simplicity-sys", features = [
+simplicity-sys = { version = "0.6.2", path = "./simplicity-sys", features = [
     "test-utils",
 ] }
 
diff --git a/simplicity-sys/Cargo.toml b/simplicity-sys/Cargo.toml
index 622949e0..35a01ed6 100644
--- a/simplicity-sys/Cargo.toml
+++ b/simplicity-sys/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "simplicity-sys"
-version = "0.6.1"
+version = "0.6.2"
 license = "CC0-1.0"
 homepage = "https://github.com/BlockstreamResearch/rust-simplicity/"
 repository = "https://github.com/BlockstreamResearch/rust-simplicity/"
diff --git a/simplicity-sys/src/c_jets/mod.rs b/simplicity-sys/src/c_jets/mod.rs
index 2cc7d864..ae2fc852 100644
--- a/simplicity-sys/src/c_jets/mod.rs
+++ b/simplicity-sys/src/c_jets/mod.rs
@@ -28,36 +28,83 @@ pub mod exec_ffi;
 ///
 /// This will also us detect whenever there is a change in the underlying C representation
 pub fn sanity_checks() -> bool {
-    unsafe {
-        if std::mem::size_of::<crate::ffi::UWORD>() != crate::ffi::c_sizeof_UWORD
-            || std::mem::align_of::<crate::ffi::UWORD>() != crate::ffi::c_alignof_UWORD
-        {
-            return false;
-        }
-
-        if std::mem::size_of::<CFrameItem>() != frame_ffi::c_sizeof_frameItem
-            || std::mem::size_of::<elements::CRawBuffer>() != c_env::elements::c_sizeof_rawBuffer
-            || std::mem::size_of::<elements::CRawInput>() != c_env::elements::c_sizeof_rawInput
-            || std::mem::size_of::<elements::CRawOutput>() != c_env::elements::c_sizeof_rawOutput
-            || std::mem::size_of::<elements::CRawTransaction>()
-                != c_env::elements::c_sizeof_rawTransaction
-            || std::mem::size_of::<elements::CTxEnv>() != c_env::elements::c_sizeof_txEnv
-            || std::mem::size_of::<elements::CRawTapEnv>() != c_env::elements::c_sizeof_rawTapEnv
-        {
-            return false;
-        }
-
-        if std::mem::align_of::<CFrameItem>() != frame_ffi::c_alignof_frameItem
-            || std::mem::align_of::<elements::CRawBuffer>() != c_env::elements::c_alignof_rawBuffer
-            || std::mem::align_of::<elements::CRawInput>() != c_env::elements::c_alignof_rawInput
-            || std::mem::align_of::<elements::CRawOutput>() != c_env::elements::c_alignof_rawOutput
-            || std::mem::align_of::<elements::CRawTransaction>()
-                != c_env::elements::c_alignof_rawTransaction
-            || std::mem::align_of::<elements::CTxEnv>() != c_env::elements::c_alignof_txEnv
-            || std::mem::align_of::<elements::CRawTapEnv>() != c_env::elements::c_alignof_rawTapEnv
-        {
-            return false;
-        }
+    sanity_check_report().is_empty()
+}
+
+#[must_use]
+pub fn sanity_check_report() -> Vec<String> {
+    let mut issues = Vec::new();
+
+    macro_rules! check_layout {
+        ($ty:ty, $c_size:path, $c_align:path, $name:expr) => {{
+            let rust_size = std::mem::size_of::<$ty>();
+            let rust_align = std::mem::align_of::<$ty>();
+            let (c_size, c_align) = unsafe { ($c_size, $c_align) };
+
+            if rust_size != c_size {
+                issues.push(format!(
+                    "{name}: size mismatch (rust={rust_size}, c={c_size})",
+                    name = $name
+                ));
+            }
+
+            if rust_align != c_align {
+                issues.push(format!(
+                    "{name}: align mismatch (rust={rust_align}, c={c_align})",
+                    name = $name
+                ));
+            }
+        }};
     }
-    true
+
+    check_layout!(
+        crate::ffi::UWORD,
+        crate::ffi::c_sizeof_UWORD,
+        crate::ffi::c_alignof_UWORD,
+        "UWORD"
+    );
+    check_layout!(
+        CFrameItem,
+        frame_ffi::c_sizeof_frameItem,
+        frame_ffi::c_alignof_frameItem,
+        "CFrameItem"
+    );
+    check_layout!(
+        elements::CRawBuffer,
+        elements::c_sizeof_rawBuffer,
+        elements::c_alignof_rawBuffer,
+        "CRawBuffer"
+    );
+    check_layout!(
+        elements::CRawInput,
+        elements::c_sizeof_rawInput,
+        elements::c_alignof_rawInput,
+        "CRawInput"
+    );
+    check_layout!(
+        elements::CRawOutput,
+        elements::c_sizeof_rawOutput,
+        elements::c_alignof_rawOutput,
+        "CRawOutput"
+    );
+    check_layout!(
+        elements::CRawTransaction,
+        elements::c_sizeof_rawTransaction,
+        elements::c_alignof_rawTransaction,
+        "CRawTransaction"
+    );
+    check_layout!(
+        elements::CTxEnv,
+        elements::c_sizeof_txEnv,
+        elements::c_alignof_txEnv,
+        "CTxEnv"
+    );
+    check_layout!(
+        elements::CRawTapEnv,
+        elements::c_sizeof_rawTapEnv,
+        elements::c_alignof_rawTapEnv,
+        "CRawTapEnv"
+    );
+
+    issues
 }
diff --git a/simplicity-sys/src/ffi.rs b/simplicity-sys/src/ffi.rs
index d2e901d5..1cdbcf03 100644
--- a/simplicity-sys/src/ffi.rs
+++ b/simplicity-sys/src/ffi.rs
@@ -21,7 +21,7 @@ pub type c_size_t = usize;
 pub type c_uint_fast8_t = u8;
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 pub type c_uint_fast16_t = u16;
-#[cfg(any(target_os = "windows", target_os = "android"))]
+#[cfg(target_os = "windows")]
 pub type c_uint_fast16_t = u32;
 #[cfg(target_arch = "wasm32")]
 pub type c_uint_fast16_t = u16;
@@ -29,7 +29,6 @@ pub type c_uint_fast16_t = u16;
     target_os = "macos",
     target_os = "ios",
     target_os = "windows",
-    target_os = "android",
     target_arch = "wasm32"
 )))]
 pub type c_uint_fast16_t = usize;
@@ -38,7 +37,6 @@ pub type c_uint_fast16_t = usize;
     target_os = "macos",
     target_os = "ios",
     target_os = "windows",
-    target_os = "android",
     target_arch = "wasm32"
 ))]
 pub type c_uint_fast32_t = u32;
@@ -46,14 +44,13 @@ pub type c_uint_fast32_t = u32;
     target_os = "macos",
     target_os = "ios",
     target_os = "windows",
-    target_os = "android",
     target_arch = "wasm32"
 )))]
 pub type c_uint_fast32_t = usize;
-#[cfg(target_arch = "wasm32")]
-pub type c_uint_fast64_t = u64;
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(target_pointer_width = "64")]
 pub type c_uint_fast64_t = usize;
+#[cfg(not(target_pointer_width = "64"))]
+pub type c_uint_fast64_t = u64;
 pub type c_uint_least32_t = u32;
 
 extern "C" {