diff --git a/artiq/firmware/Cargo.lock b/artiq/firmware/Cargo.lock
index a60de7ea9..794b0e2d3 100644
--- a/artiq/firmware/Cargo.lock
+++ b/artiq/firmware/Cargo.lock
@@ -126,7 +126,7 @@ dependencies = [
  "alloc_stub 0.0.0",
  "amp 0.0.0",
  "board 0.0.0",
- "build_artiq 0.0.0",
+ "build_misoc 0.0.0",
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.0 (git+https://github.com/m-labs/compiler-builtins?rev=97916b1)",
  "cslice 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -185,6 +185,7 @@ dependencies = [
  "board 0.0.0",
  "board_artiq 0.0.0",
  "build_artiq 0.0.0",
+ "build_misoc 0.0.0",
  "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.0 (git+https://github.com/m-labs/compiler-builtins?rev=97916b1)",
  "cslice 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/artiq/firmware/ksupport/Cargo.toml b/artiq/firmware/ksupport/Cargo.toml
index 1162a848c..b295c160c 100644
--- a/artiq/firmware/ksupport/Cargo.toml
+++ b/artiq/firmware/ksupport/Cargo.toml
@@ -10,7 +10,7 @@ path = "lib.rs"
 crate-type = ["staticlib"]
 
 [build-dependencies]
-build_artiq = { path = "../libbuild_artiq" }
+build_misoc = { path = "../libbuild_misoc" }
 
 [dependencies]
 byteorder = { version = "1.0", default-features = false }
diff --git a/artiq/firmware/ksupport/build.rs b/artiq/firmware/ksupport/build.rs
index 6f802af66..ab6acff39 100644
--- a/artiq/firmware/ksupport/build.rs
+++ b/artiq/firmware/ksupport/build.rs
@@ -1,6 +1,6 @@
-extern crate build_artiq;
+extern crate build_misoc;
 
 fn main() {
-    build_artiq::misoc_cfg();
+    build_misoc::cfg();
     println!("cargo:rustc-cfg={}", "ksupport");
 }
diff --git a/artiq/firmware/libboard_artiq/build.rs b/artiq/firmware/libboard_artiq/build.rs
index 225cf707a..508c9f935 100644
--- a/artiq/firmware/libboard_artiq/build.rs
+++ b/artiq/firmware/libboard_artiq/build.rs
@@ -1,10 +1,9 @@
 extern crate build_misoc;
-extern crate build_artiq;
 
 use std::env;
 use std::fs::File;
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::Path;
 use std::process::Command;
 
 fn gen_hmc7043_writes() {
@@ -19,8 +18,8 @@ fn gen_hmc7043_writes() {
                 .ok()
                 .and_then(|o| String::from_utf8(o.stdout).ok())
                 .unwrap();
-    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-    let mut f = File::create(out_dir.join("hmc7043_writes.rs")).unwrap();
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let mut f = File::create(Path::new(&out_dir).join("hmc7043_writes.rs")).unwrap();
     write!(f, "{}", hmc7043_writes).unwrap();
 }
 
diff --git a/artiq/firmware/libbuild_artiq/lib.rs b/artiq/firmware/libbuild_artiq/lib.rs
index 2eb27a040..cd35a30a8 100644
--- a/artiq/firmware/libbuild_artiq/lib.rs
+++ b/artiq/firmware/libbuild_artiq/lib.rs
@@ -2,8 +2,8 @@ extern crate walkdir;
 
 use std::env;
 use std::fs::File;
-use std::io::{Write, BufRead, BufReader};
-use std::path::{Path, PathBuf};
+use std::io::Write;
+use std::path::Path;
 use std::process::Command;
 
 use walkdir::WalkDir;
@@ -42,18 +42,7 @@ pub fn git_describe() {
         version = "unknown".to_owned();
     }
 
-    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-    let mut f = File::create(out_dir.join("git-describe")).unwrap();
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let mut f = File::create(Path::new(&out_dir).join("git-describe")).unwrap();
     write!(f, "{}", version).unwrap();
 }
-
-pub fn misoc_cfg() {
-    let out_dir = env::var("BUILDINC_DIRECTORY").unwrap();
-    let cfg_path = Path::new(&out_dir).join("generated").join("rust-cfg");
-    println!("cargo:rerun-if-changed={}", cfg_path.to_str().unwrap());
-
-    let f = BufReader::new(File::open(&cfg_path).unwrap());
-    for line in f.lines() {
-        println!("cargo:rustc-cfg={}", line.unwrap());
-    }
-}
diff --git a/artiq/firmware/runtime/Cargo.toml b/artiq/firmware/runtime/Cargo.toml
index 6753261cd..5802b84b2 100644
--- a/artiq/firmware/runtime/Cargo.toml
+++ b/artiq/firmware/runtime/Cargo.toml
@@ -10,6 +10,7 @@ crate-type = ["staticlib"]
 path = "main.rs"
 
 [build-dependencies]
+build_misoc = { path = "../libbuild_misoc" }
 build_artiq = { path = "../libbuild_artiq" }
 
 [dependencies]
diff --git a/artiq/firmware/runtime/build.rs b/artiq/firmware/runtime/build.rs
index d9df648a6..64a84fcb8 100644
--- a/artiq/firmware/runtime/build.rs
+++ b/artiq/firmware/runtime/build.rs
@@ -1,6 +1,7 @@
+extern crate build_misoc;
 extern crate build_artiq;
 
 fn main() {
+    build_misoc::cfg();
     build_artiq::git_describe();
-    build_artiq::misoc_cfg();
 }
diff --git a/artiq/firmware/satman/Cargo.toml b/artiq/firmware/satman/Cargo.toml
index be6abc55f..7cab6d4c1 100644
--- a/artiq/firmware/satman/Cargo.toml
+++ b/artiq/firmware/satman/Cargo.toml
@@ -10,6 +10,7 @@ crate-type = ["staticlib"]
 path = "main.rs"
 
 [build-dependencies]
+build_misoc = { path = "../libbuild_misoc" }
 build_artiq = { path = "../libbuild_artiq" }
 
 [dependencies]
diff --git a/artiq/firmware/satman/build.rs b/artiq/firmware/satman/build.rs
index d9df648a6..64a84fcb8 100644
--- a/artiq/firmware/satman/build.rs
+++ b/artiq/firmware/satman/build.rs
@@ -1,6 +1,7 @@
+extern crate build_misoc;
 extern crate build_artiq;
 
 fn main() {
+    build_misoc::cfg();
     build_artiq::git_describe();
-    build_artiq::misoc_cfg();
 }