Fixed "UnicodeEncodeError" when a build output contains non-ASCII characters // Resolve #3971

platformio/platform/_run.py

@@ -110,6 +110,8 @@ class PlatformRunMixin(object):
             args.append("%s=%s" % (key.upper(), self.encode_scons_arg(value)))
 
         proc.copy_pythonpath_to_osenv()
+        # force SCons output to Unicode
+        os.environ["PYTHONIOENCODING"] = "utf-8"
 
         if targets and "menuconfig" in targets:
             return proc.exec_command(