diff --git a/zh-cn/device-dev/porting/porting-stm32f407-on-minisystem-eth.md b/zh-cn/device-dev/porting/porting-stm32f407-on-minisystem-eth.md
index 491060cb07bb0998b562d6285069a3967ba3c6a6..6d30ba1b1b9b0432e40659c6124a6042e05d2950 100644
--- a/zh-cn/device-dev/porting/porting-stm32f407-on-minisystem-eth.md
+++ b/zh-cn/device-dev/porting/porting-stm32f407-on-minisystem-eth.md
@@ -637,7 +637,7 @@ board_ld_flags  ：链接选项，与Makefile中的LDFLAGS变量对应。
    
        sources += [
            "Src/main.c",
-   +       "Src/dprintf.c",
+           "Src/dprintf.c",
            "Src/stm32f4xx_hal_msp.c",
            "Src/stm32f4xx_it.c",
            "Src/system_stm32f4xx.c",