diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 00000000..a5535e34
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,2 @@
+[toolchain]
+channel = "dev-x86_64-unknown-mikros"
diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs
index 99a2d5d0..7dd5c61c 100644
--- a/serde/src/de/impls.rs
+++ b/serde/src/de/impls.rs
@@ -1898,17 +1898,17 @@ forwarded_impl! {
 //
 //    #[derive(Deserialize)]
 //    #[serde(variant_identifier)]
-#[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
 variant_identifier! {
     OsStringKind (Unix; b"Unix"; 0, Windows; b"Windows"; 1)
     "`Unix` or `Windows`",
     OSSTR_VARIANTS
 }
 
-#[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
 struct OsStringVisitor;
 
-#[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
 impl<'de> Visitor<'de> for OsStringVisitor {
     type Value = OsString;
 
@@ -1916,12 +1916,15 @@ impl<'de> Visitor<'de> for OsStringVisitor {
         formatter.write_str("os string")
     }
 
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "mikros"))]
     fn visit_enum<A>(self, data: A) -> Result<Self::Value, A::Error>
     where
         A: EnumAccess<'de>,
     {
+        #[cfg(unix)]
         use std::os::unix::ffi::OsStringExt;
+        #[cfg(target_os = "mikros")]
+        use std::os::mikros::ffi::OsStringExt;
 
         match tri!(data.variant()) {
             (OsStringKind::Unix, v) => v.newtype_variant().map(OsString::from_vec),
@@ -1949,8 +1952,8 @@ impl<'de> Visitor<'de> for OsStringVisitor {
     }
 }
 
-#[cfg(all(feature = "std", any(unix, windows)))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))))]
 impl<'de> Deserialize<'de> for OsString {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1981,8 +1984,8 @@ forwarded_impl! {
 }
 
 forwarded_impl! {
-    #[cfg(all(feature = "std", any(unix, windows)))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+    #[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
+    #[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))))]
     (), Box<OsStr>, OsString::into_boxed_os_str
 }
 
@@ -3210,10 +3213,11 @@ impl<'de> Visitor<'de> for ErrnoVisitor {
     where
         E: Error,
     {
-        if let Ok(errno) = Errno::try_from(v) {
+        use std::convert::TryFrom;
+        if let Ok(errno) = std::os::mikros::Errno::try_from(v) {
             Ok(errno)
         } else {
-            Err(E::invalid_value(Unexpected::Signed(v as i32), "errno"))
+            Err(E::invalid_value(Unexpected::Signed(v as i64), &self))
         }
     }
 }
diff --git a/serde/src/ser/impls.rs b/serde/src/ser/impls.rs
index 801ea0cb..bb3e27b4 100644
--- a/serde/src/ser/impls.rs
+++ b/serde/src/ser/impls.rs
@@ -979,15 +979,19 @@ impl Serialize for PathBuf {
     }
 }
 
-#[cfg(all(feature = "std", any(unix, windows)))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))))]
 impl Serialize for OsStr {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "mikros"))]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
     {
+
+        #[cfg(unix)]
         use std::os::unix::ffi::OsStrExt;
+        #[cfg(target_os = "mikros")]
+        use std::os::mikros::ffi::OsStrExt;
         serializer.serialize_newtype_variant("OsString", 0, "Unix", self.as_bytes())
     }
 
@@ -1002,8 +1006,8 @@ impl Serialize for OsStr {
     }
 }
 
-#[cfg(all(feature = "std", any(unix, windows)))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+#[cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows, target_os = "mikros")))))]
 impl Serialize for OsString {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -1104,6 +1108,6 @@ impl Serialize for std::os::mikros::Errno {
     where
         S: Serializer,
     {
-        (self as i32).serialize(serializer)
+        (*self as i32).serialize(serializer)
     }
 }