diff --git a/crates/khal/src/backend/cuda.rs b/crates/khal/src/backend/cuda.rs
index b734819..cf715e9 100644
--- a/crates/khal/src/backend/cuda.rs
+++ b/crates/khal/src/backend/cuda.rs
@@ -271,9 +271,16 @@ impl Backend for Cuda {
             }
         }
 
-        // Expect PTX text bytes.
-        let ptx_str = std::str::from_utf8(bytes).map_err(|_| CudaBackendError::InvalidPtx)?;
-        let ptx = cudarc::nvrtc::Ptx::from_src(ptx_str.to_string());
+        // Accept either PTX text or a pre-linked CUBIN (detected by ELF magic).
+        // A cubin is required when the module references symbols the driver JIT
+        // cannot resolve on its own (e.g. libdevice `__nv_*` math), which a
+        // toolchain links into a self-contained binary ahead of time.
+        let ptx = if bytes.starts_with(&[0x7f, b'E', b'L', b'F']) {
+            cudarc::nvrtc::Ptx::from_binary(bytes.to_vec())
+        } else {
+            let ptx_str = std::str::from_utf8(bytes).map_err(|_| CudaBackendError::InvalidPtx)?;
+            cudarc::nvrtc::Ptx::from_src(ptx_str.to_string())
+        };
         let module = self.ctx.load_module(ptx)?;
 
         // Cache the loaded module.