diff --git a/macros/Cargo.toml b/macros/Cargo.toml
index a9f268fbf8..ffa353c5af 100644
--- a/macros/Cargo.toml
+++ b/macros/Cargo.toml
@@ -22,5 +22,6 @@ proc-macro2 = "1"
 proc-macro-error = "1"
 quote = "1"
 syn = "1"
-rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "master", version = "0.5.0-alpha.0" }
+#rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "master", version = "0.5.0-alpha.0" }
+rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "extern_task", version = "0.5.0-alpha.0" }
 
diff --git a/macros/src/codegen/hardware_tasks.rs b/macros/src/codegen/hardware_tasks.rs
index e5a8deb9e8..c9d0297ea1 100644
--- a/macros/src/codegen/hardware_tasks.rs
+++ b/macros/src/codegen/hardware_tasks.rs
@@ -95,19 +95,21 @@ pub fn codegen(
             locals_pat = Some(pat);
         }
 
-        let attrs = &task.attrs;
-        let context = &task.context;
-        let stmts = &task.stmts;
-        let locals_pat = locals_pat.iter();
-        user_tasks.push(quote!(
-            #(#attrs)*
-            #[allow(non_snake_case)]
-            fn #name(#(#locals_pat,)* #context: #name::Context) {
-                use rtic::Mutex as _;
+        if !&task.is_extern {
+            let attrs = &task.attrs;
+            let context = &task.context;
+            let stmts = &task.stmts;
+            let locals_pat = locals_pat.iter();
+            user_tasks.push(quote!(
+                #(#attrs)*
+                #[allow(non_snake_case)]
+                fn #name(#(#locals_pat,)* #context: #name::Context) {
+                    use rtic::Mutex as _;
 
-                #(#stmts)*
-            }
-        ));
+                    #(#stmts)*
+                }
+            ));
+        }
     }
 
     (mod_app, root, user_tasks)
diff --git a/macros/src/codegen/software_tasks.rs b/macros/src/codegen/software_tasks.rs
index dfba193bc8..833e338dd5 100644
--- a/macros/src/codegen/software_tasks.rs
+++ b/macros/src/codegen/software_tasks.rs
@@ -99,21 +99,23 @@ pub fn codegen(
             root.push(struct_);
         }
 
-        let context = &task.context;
-        let attrs = &task.attrs;
-        let cfgs = &task.cfgs;
-        let stmts = &task.stmts;
-        let locals_pat = locals_pat.iter();
-        user_tasks.push(quote!(
-            #(#attrs)*
-            #(#cfgs)*
-            #[allow(non_snake_case)]
-            fn #name(#(#locals_pat,)* #context: #name::Context #(,#inputs)*) {
-                use rtic::Mutex as _;
+        if !&task.is_extern {
+            let context = &task.context;
+            let attrs = &task.attrs;
+            let cfgs = &task.cfgs;
+            let stmts = &task.stmts;
+            let locals_pat = locals_pat.iter();
+            user_tasks.push(quote!(
+                #(#attrs)*
+                #(#cfgs)*
+                #[allow(non_snake_case)]
+                fn #name(#(#locals_pat,)* #context: #name::Context #(,#inputs)*) {
+                    use rtic::Mutex as _;
 
-                #(#stmts)*
-            }
-        ));
+                    #(#stmts)*
+                }
+            ));
+        }
 
         root.push(module::codegen(
             Context::SoftwareTask(name),