diff --git a/src/boot_info.rs b/src/boot_info.rs
index 9d902cf..74e6806 100644
--- a/src/boot_info.rs
+++ b/src/boot_info.rs
@@ -395,7 +395,10 @@
             return Err(Error::InvalidSignature);
         }
 
-        let header_version = header_raw.version.into();
+        let header_version = header_raw
+            .version
+            .try_into()
+            .map_err(|_| Error::InvalidHeader)?;
         if header_version != version {
             return Err(Error::InvalidVersion(header_version));
         }
diff --git a/src/lib.rs b/src/lib.rs
index ae66d12..dc965ef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -203,6 +203,9 @@
 pub struct Version(pub u16, pub u16);
 
 impl Version {
+    // The FF-A spec mandates that bit[31] of a version number must be 0
+    const MBZ_BITS: u32 = 1 << 31;
+
     /// Returns whether the caller's version (self) is compatible with the callee's version (input
     /// parameter)
     pub fn is_compatible_to(&self, callee_version: &Version) -> bool {
@@ -210,15 +213,23 @@
     }
 }
 
-impl From<u32> for Version {
-    fn from(val: u32) -> Self {
-        Self((val >> 16) as u16, val as u16)
+impl TryFrom<u32> for Version {
+    type Error = Error;
+
+    fn try_from(val: u32) -> Result<Self, Self::Error> {
+        if (val & Self::MBZ_BITS) != 0 {
+            Err(Error::InvalidVersion(val))
+        } else {
+            Ok(Self((val >> 16) as u16, val as u16))
+        }
     }
 }
 
 impl From<Version> for u32 {
     fn from(v: Version) -> Self {
-        ((v.0 as u32) << 16) | v.1 as u32
+        let v_u32 = ((v.0 as u32) << 16) | v.1 as u32;
+        assert!(v_u32 & Version::MBZ_BITS == 0);
+        v_u32
     }
 }
 
@@ -705,7 +716,7 @@
                 interrupt_id: regs[2] as u32,
             },
             FuncId::Version => Self::Version {
-                input_version: (regs[1] as u32).into(),
+                input_version: (regs[1] as u32).try_into()?,
             },
             FuncId::Features => Self::Features {
                 feat_id: (regs[1] as u32).into(),