diff --git a/.github/workflows/build_all.yml b/.github/workflows/build_all.yml
index 0016ea7ec..b08bff692 100644
--- a/.github/workflows/build_all.yml
+++ b/.github/workflows/build_all.yml
@@ -1,12 +1,12 @@
-name: build all
+name: build main
 
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
     branches:
-      - master
+      - main
 
 jobs:
   build:
diff --git a/README_zh.md b/README_zh.md
index 99fd51f05..34aac25c5 100644
--- a/README_zh.md
+++ b/README_zh.md
@@ -2,10 +2,12 @@
 
 [English Version](README.md)
 
-# 简介
-
 **BouffaloSDK** 是 Bouffalo Lab 提供的 IOT 和 MCU 软件开发包，支持博流智能所有系列芯片，也是 **bl_mcu_sdk** 和 **bl_iot_sdk** 的结合体。
 
+
+* [Ai-M6X_SDK](https://github.com/Ai-Thinker-Open/aithinker_Ai-M6X_SDK)
+* [M1s_BL808_example](https://github.com/sipeed/M1s_BL808_example)
+
 # SDK 架构
 
 ![SDK Architecture](BouffaloSDK.png)
diff --git a/examples/printf/README.md b/examples/printf/README.md
index e2f443074..400bb50ce 100644
--- a/examples/printf/README.md
+++ b/examples/printf/README.md
@@ -33,12 +33,18 @@ make CHIP=bl616 BOARD=bl616dk
 - BL808
 
 ```
-make CHIP=bl808 BOARD=bl808dk CPU_ID=m0
 make CHIP=bl808 BOARD=bl808dk CPU_ID=d0
+make CHIP=bl808 BOARD=bl808dk CPU_ID=m0
+
 ```
 
 ## Flash
 
 ```
 make flash CHIP=chip_name COMX=xxx # xxx is your com name
+
+make flash CHIP=bl616 COMX=/dev/ttyUSB0
+
+make flash CHIP=bl808 CPU_ID=d0 COMX=/dev/ttyUSB1
+make flash CHIP=bl808 CPU_ID=m0 COMX=/dev/ttyUSB1
 ```
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