diff --git a/builder/frameworks/_build_pioasm.py b/builder/frameworks/_build_pioasm.py
index b5bdafc..0b11bfd 100644
--- a/builder/frameworks/_build_pioasm.py
+++ b/builder/frameworks/_build_pioasm.py
@@ -7,6 +7,7 @@
 env = DefaultEnvironment()
 
 PROJECT_SRC_DIR = Path(env['PROJECT_SRC_DIR'])
+LIB_SRC_DIR = Path(env['PROJECT_LIBDEPS_DIR']) / env['PIOENV']
 
 # Find the bundled pioasm executable
 pioasm_dir = env.PioPlatform().get_package_dir("tool-pioasm-rp2040-earlephilhower")
@@ -16,14 +17,25 @@ def pio_to_pioh_cmd(pio_file: Path) -> str:
     header_file = pio_file.with_suffix(".pio.h")
     return f'"{pioasm_exe}" -o c-sdk "{pio_file}" "{header_file}"'
 
-# Process all .pio files in PROJECT_SRC_DIR
-for pio_file in PROJECT_SRC_DIR.rglob("*.pio"):
-    header_file = pio_file.with_suffix(".pio.h")
+def process_pio_files(src_dir: Path):
+    """Process all .pio files in the given directory"""
+    for pio_file in src_dir.rglob("*.pio"):
+        # Skip if not a file (e.g. directory named .pio)
+        if not pio_file.is_file():
+            continue
+
+        header_file = pio_file.with_suffix(".pio.h")
+
+        # Only rebuild if missing or outdated
+        if not header_file.exists() or pio_file.stat().st_mtime > header_file.stat().st_mtime:
+            action = env.VerboseAction(pio_to_pioh_cmd(pio_file), f"Building {header_file}")
+            ret = env.Execute(action)
+            if ret != 0:
+                print(f"[ERROR] Failed to build {pio_file}, stopping.", file=sys.stderr)
+                sys.exit(1)
+
+# Process project source files
+process_pio_files(PROJECT_SRC_DIR)
 
-    # Only rebuild if missing or outdated
-    if not header_file.exists() or pio_file.stat().st_mtime > header_file.stat().st_mtime:
-        action = env.VerboseAction(pio_to_pioh_cmd(pio_file), f"Building {header_file}")
-        ret = env.Execute(action)
-        if ret != 0:
-            print(f"[ERROR] Failed to build {pio_file}, stopping.", file=sys.stderr)
-            sys.exit(1)
+# Process library source files
+process_pio_files(LIB_SRC_DIR)