Add checksum calc for bin file

post_build.py

@@ -0,0 +1,25 @@
+Import("env")
+
+from pathlib import Path
+import hashlib
+
+
+print("Current CLI targets", COMMAND_LINE_TARGETS)
+print("Current Build targets", BUILD_TARGETS)
+
+def sha256sum(filename):
+    with open(filename, 'rb', buffering=0) as f:
+        return hashlib.file_digest(f, 'sha256').hexdigest()
+
+def post_buildprog_action(source, target, env):
+    source_path = Path(source[0].get_abspath())
+    sha256 = sha256sum(source_path)
+    print(f"Calculated SHA256: {sha256}")
+
+    build_dir = source_path.parent
+    sha_txt_file = build_dir / "firmware.bin.sha256"
+
+    with Path.open(sha_txt_file, "w") as f:
+        f.write(sha256)
+
+env.AddPostAction("buildprog", post_buildprog_action)