diff --git a/xous-rs/src/definitions.rs b/xous-rs/src/definitions.rs
index 3867cf6a1..138bf9d83 100644
--- a/xous-rs/src/definitions.rs
+++ b/xous-rs/src/definitions.rs
@@ -463,6 +463,9 @@ pub enum Result {
     /// 20: A scalar with five values
     Scalar5(usize, usize, usize, usize, usize),
 
+    // 21: A message is returned as part of `send_message()` when the result is blocking
+    Message(Message),
+
     UnknownResult(usize, usize, usize, usize, usize, usize, usize),
 }
 
@@ -526,7 +529,13 @@ impl Result {
                 0,
             ],
             Result::NewProcess(p) => Self::add_opcode(19, p.into()),
-            Result::Scalar5(a, b, c, d, e) => [15, *a, *b, *c, *d, *e, 0, 0],
+            Result::Scalar5(a, b, c, d, e) => [20, *a, *b, *c, *d, *e, 0, 0],
+            Result::Message(message) => {
+                let encoded = message.to_usize();
+                [
+                    21, encoded[0], encoded[1], encoded[2], encoded[3], encoded[4], encoded[5], 0,
+                ]
+            }
             Result::UnknownResult(arg1, arg2, arg3, arg4, arg5, arg6, arg7) => {
                 [usize::MAX, *arg1, *arg2, *arg3, *arg4, *arg5, *arg6, *arg7]
             }
@@ -605,19 +614,36 @@ impl Result {
             18 => Result::MemoryReturned(MemorySize::new(src[1]), MemorySize::new(src[2])),
             19 => Result::NewProcess(src.into()),
             20 => Result::Scalar5(src[1], src[2], src[3], src[4], src[5]),
+            21 => Result::Message(match src[1] {
+                0 => match MemoryMessage::from_usize(src[2], src[3], src[4], src[5], src[6]) {
+                    None => return Result::Error(Error::InternalError),
+                    Some(s) => Message::MutableBorrow(s),
+                },
+                1 => match MemoryMessage::from_usize(src[2], src[3], src[4], src[5], src[6]) {
+                    None => return Result::Error(Error::InternalError),
+                    Some(s) => Message::Borrow(s),
+                },
+                2 => match MemoryMessage::from_usize(src[2], src[3], src[4], src[5], src[6]) {
+                    None => return Result::Error(Error::InternalError),
+                    Some(s) => Message::Move(s),
+                },
+                3 => Message::Scalar(ScalarMessage::from_usize(
+                    src[2], src[3], src[4], src[5], src[6],
+                )),
+                4 => Message::BlockingScalar(ScalarMessage::from_usize(
+                    src[2], src[3], src[4], src[5], src[6],
+                )),
+                _ => return Result::Error(Error::InternalError),
+            }),
             _ => Result::UnknownResult(src[0], src[1], src[2], src[3], src[4], src[5], src[6]),
         }
     }
 
     /// If the Result has memory attached to it, return the memory
-    pub fn memory(&self) -> Option<MemoryRange> {
+    pub fn memory(&self) -> Option<&MemoryRange> {
         match self {
-            Result::Message(msg) => match &msg.body {
-                Message::Move(memory_message)
-                | Message::Borrow(memory_message)
-                | Message::MutableBorrow(memory_message) => Some(memory_message.buf),
-                _ => None,
-            },
+            Result::MessageEnvelope(msg) => msg.body.memory(),
+            Result::Message(msg) => msg.memory(),
             _ => None,
         }
     }
diff --git a/xous-rs/src/definitions/messages/mod.rs b/xous-rs/src/definitions/messages/mod.rs
index 53ed4897c..a3d5fa7fc 100644
--- a/xous-rs/src/definitions/messages/mod.rs
+++ b/xous-rs/src/definitions/messages/mod.rs
@@ -264,6 +264,19 @@ impl Message {
             Message::Scalar(s) | Message::BlockingScalar(s) => s.id = id,
         }
     }
+
+    pub fn to_usize(&self) -> [usize; 6] {
+        let ret = match &*self {
+            Message::MutableBorrow(m) => (0, m.to_usize()),
+            Message::Borrow(m) => (1, m.to_usize()),
+            Message::Move(m) => (2, m.to_usize()),
+            Message::Scalar(m) => (3, m.to_usize()),
+            Message::BlockingScalar(m) => (4, m.to_usize()),
+        };
+        [
+            ret.0, ret.1[0], ret.1[1], ret.1[2], ret.1[3], ret.1[4],
+        ]
+    }
 }
 
 impl TryFrom<(usize, usize, usize, usize, usize, usize)> for Message {
diff --git a/xous-rs/src/syscall.rs b/xous-rs/src/syscall.rs
index 7e799be86..6082f8343 100644
--- a/xous-rs/src/syscall.rs
+++ b/xous-rs/src/syscall.rs
@@ -324,11 +324,14 @@ pub enum SysCall {
     ///
     /// # Returns
     ///
-    /// * **Ok**: The Scalar / Send message was successfully sent, or the Borrow has finished
+    /// * **Ok**: The Scalar / Send message was successfully sent
     /// * **Scalar1**: The Server returned a `Scalar1` value
     /// * **Scalar2**: The Server returned a `Scalar2` value
     /// * **Scalar5**: The Server returned a `Scalar5` value
     /// * **BlockedProcess**: In Hosted mode, the target process is now blocked
+    /// * **Message**: For Scalar messages, this includes the args as returned
+    ///                 by the server. For MemoryMessages, this will include
+    ///                 the Opcode, Offset, and Valid fields.
     ///
     /// # Errors
     ///
@@ -511,6 +514,7 @@ pub enum SysCall {
         usize,         /* arg2 (BlockingScalar) or the memory length (MemoryMesage) */
         usize,         /* arg3 (BlockingScalar) or the memory offset (MemoryMesage) */
         usize,         /* arg4 (BlockingScalar) or the memory valid (MemoryMesage) */
+        usize,         /* for BlockingScalars, indicates how many args are valid */
     ),
 
     /// This syscall does not exist. It captures all possible