diff --git a/tools/pioarduino-build.py b/tools/pioarduino-build.py
index 3335a716888..b6a0c0435c5 100644
--- a/tools/pioarduino-build.py
+++ b/tools/pioarduino-build.py
@@ -99,11 +99,11 @@ def generate_bootloader_image(bootloader_elf):
                     "--chip",
                     build_mcu,
                     "elf2image",
-                    "--flash_mode",
+                    "--flash-mode",
                     "${__get_board_flash_mode(__env__)}",
-                    "--flash_freq",
+                    "--flash-freq",
                     "${__get_board_f_image(__env__)}",
-                    "--flash_size",
+                    "--flash-size",
                     board_config.get("upload.flash_size", "4MB"),
                     "-o",
                     "$TARGET",