1. Overview¶

1.1. Scope of application¶

RK3399 Android7.1 Industry
RK3399 Android10
RK356X Android11
RK3588 Android12

For other Android versions, it is available for reference.

1.2. Modification method¶

For Android system customization, there are generally Temporary modification methods and Code modification methods.

Temporary modification method：Generally, the device can be operated through the debug serial port or ADB.
Code modification method：After modifying the code, you need to perform SDK compilation and firmware flashing.

Among them, SDK compilation or firmware flashing refer to WiKi tutorial。

1.3. Glossary¶

CPU_TYPE：Indicates the main control chip, such as rk3288, rk3399, rk3399pro, rk356x, rk3588
PRODUCT_TYPE：Indicates the product type, such as rk3399_firefly, rk3399_firefly_aio, rk3399_firefly_aioc_ai

1.4. Custom description¶

For the customized content of the system, there will be some differences in Android12, Android11, Android10.0 and Android7.1 Industry. This part of the content will be distinguished, and the undifferentiated content indicates compatibility.

2. Boot logo animation modification¶

2.1. The first stage¶

2.1.1. Code modification method¶

Prepare the logo
- Make a new logo.bmp
  - The image attributes are the same as the default logo.bmp, otherwise an upside-down exception will occur
  - Both width and height are even numbers
Replace logo
- Replace kernel/logo.bmp

2.2. Second stage¶

2.2.1. Temporary modification method¶

Prepare bootanimation.zip
- Prepare png file
  - Both width and height are even numbers
- Prepare desc.txt file, such as
```
800 1280 30
p 0 0 part0
```
  - 800 1280 30Meaning: the first two numbers represent the pixel width and height of the picture, 30 represents the number of frames, which is the number of pictures played in 1 second
  - p 0 0 part0Meaning: p stands for flag bit, 0 stands for infinite loop, 0 stands for the interval time between stages is 0, part0 stands for the corresponding folder
  - desc.txt text format: Unix+UTF-8
- Make bootanimation.zip
  - Compressed into a zip file in storage method

Push bootanimation.zip

adb shell setprop persist.sys.root_access 3
adb root
adb remount
adb push bootanimation.zip system/media/bootanimation.zip
adb shell reboot

2.2.2. Code modification method¶

Prepare bootanimation.zip
- Put the prepared bootanimation.zip into the device/rockchip/CPU_TYPE/ directory

In the device/rockchip/CPU_TYPE/device.mk file, add the following content:

PRODUCT_COPY_FILES += \
       device/rockchip/CPU_TYPE/bootanimation.zip:/system/media/bootanimation.zip

3. Default screen orientation modification¶

3.1. Temporary modification method¶

System readable and writable

adb shell setprop persist.sys.root_access 3
adb root
adb remount

Modify or add attribute values
- Android7.1
  - In the /system/build.prop file, modify or add the value of ro.sf.hwrotation
    - 0：Horizontal screen
    - 90：Portrait
    - 180：Reverse landscape
    - 270：Reverse portrait
- Android10 and above
  - In the vendor/build.prop file, modify or add the value of ro.surface_flinger.primary_display_orientation
    - ORIENTATION_0：Horizontal screen
    - ORIENTATION_90：Portrait
    - ORIENTATION_180：Reverse landscape
    - ORIENTATION_270：Reverse portrait
System restart
```
adb shell reboot
```

3.2. Code modification method¶

Android 7.1:

In the file device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop, modify the value of ro.sf.hwrotation
Android10 and above:

In the file device/rockchip/CPU_TYPE/BoardConfig.mk, modify the value of SF_PRIMARY_DISPLAY_ORIENTATION
- 0：Horizontal screen
- 90：Portrait
- 180：Reverse landscape
- 270：Reverse portrait

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

4. Hide the status bar by default¶

4.1. Temporary modification method¶

In the Settings, just enable the option.

Settings–>Display–>Always hide the status bar

4.1.1. Code modification method¶

The revised content is as follows

diff --git a/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml b/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
index ba87da7ec4..e32c9699f9 100644
--- a/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
+++ b/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
@@ -12,7 +12,7 @@
     <!-- should show the hidebar button default -->
     <bool name="def_hidebar_button_show">true</bool>
     <!-- always hide statusbar -->
-    <bool name="def_always_hide_bar">false</bool>
+    <bool name="def_always_hide_bar">true</bool>

     <!-- will set DEFAULT_LAUNCHER in frist boot -->
     <string name="def_default_launcher" translatable="false"></string>

5. Several ways of setting built-in APP¶

5.1. Code modification method¶

App folders can be added under the vendor directory

5.1.1. Not uninstallable¶

Refer to vendor/firefly/fireflyapi

Contents in Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := firefly_sdkapi_demo
LOCAL_MODULE_CLASS := APPS
LOCAL_MODULE_TAGS := optional
LOCAL_BUILT_MODULE_STEM := package.apk
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
#LOCAL_PRIVILEGED_MODULE :=
LOCAL_CERTIFICATE := platform
#LOCAL_OVERRIDES_PACKAGES := 
LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
#LOCAL_REQUIRED_MODULES :=
#LOCAL_PREBUILT_JNI_LIBS :=
include $(BUILD_PREBUILT)

LOCAL_CERTIFICATE := platform Meaning: APK signature uses system signature
LOCAL_PRIVILEGED_MODULE If not set or set to false, the installation location is /system/app

Contents in fireflyapi.mk

PRODUCT_PACKAGES += \
   	firefly_sdkapi_demo 

PRODUCT_COPY_FILES += \
       vendor/firefly/fireflyapi/fireflyapi:system/bin/fireflyapi \
       vendor/firefly/fireflyapi/fireflyapi.jar:system/framework/fireflyapi.jar 

5.1.2. Uninstallable¶

mkdir device/rockchip/CPU_TYPE/PRODUCT_TYPE/preinstall_del
copy apk to device/rockchip/CPU_TYPE/PRODUCT_TYPE/preinstall_del
build android

6. Setting of built-in default input method¶

6.1. Code modification method¶

Get the input method package name

adb shell settings get secure enabled_input_methods
com.android.inputmethod.latin/.LatinIME:com.iflytek.inputmethod.google/com.iflytek.inputmethod.FlyIME:com.google.android.inputmethod.pinyin/.PinyinIME
adb shell settings get secure default_input_method
com.iflytek.inputmethod.google/com.iflytek.inputmethod.FlyIME

Modify the code as follows

diff --git a/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml b/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
index ba87da7ec4..7ed79b4c15 100644
--- a/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
+++ b/frameworks/base/packages/SettingsProvider/res/values/custom_defaults.xml
@@ -19,4 +19,7 @@

     <!-- if 1 ,reboot will reset DEFAULT_LAUNCHER -->
     <bool name="def_lock_default_launcher">false</bool>
+
+       <string name="enabled_input_methods" translatable="false">com.android.inputmethod.latin/.LatinIME:com.iflytek.inputmethod.google/com.iflytek.inputmethod.FlyIME:com.google.android.inputmethod.pinyin/.PinyinIME</string>
+       <string name="def_input_method" translatable="false">com.iflytek.inputmethod.google/com.iflytek.inputmethod.FlyIME</string>
 </resources>

diff --git a/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java b/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
index cac5f800bd..f705a895b4 100644
--- a/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
+++ b/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
@@ -2474,6 +2474,11 @@ class DatabaseHelper extends SQLiteOpenHelper {
             stmt = db.compileStatement("INSERT OR IGNORE INTO secure(name,value)"
                     + " VALUES(?,?);");

+                       loadStringSetting(stmt, Settings.Secure.ENABLED_INPUT_METHODS,
+                                       R.string.enabled_input_methods);
+                       loadStringSetting(stmt, Settings.Secure.DEFAULT_INPUT_METHOD,
+                                       R.string.def_input_method);
+
             loadStringSetting(stmt, Settings.Secure.LOCATION_PROVIDERS_ALLOWED,
                     R.string.def_location_providers_allowed);

7. Delete built-in apps¶

7.1. Temporary modification method¶

adb shell setprop persist.sys.root_access 3
adb root
adb remount
adb shell rm -r system/app/APK_NAME/
adb shell reboot

or

adb shell setprop persist.sys.root_access 3
adb root
adb remount
adb shell rm -r system/priv-app/APK_NAME/
adb shell reboot

7.2. Code modification method¶

If the application has source code, comment out the include $(BUILD_PACKAGE) in the Android.mk file of the application source code
If the application is an APK file and has Android.mk, comment out include $(BUILD_PREBUILT) in the Android.mk file

8. Startup application¶

8.1. Code modification method¶

8.1.1. Non-launcher¶

Add the following content to the AndroidManifest.xml in the application source code

package="com.example.testfile"
android:sharedUserId="android.uid.system">

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

<receiver android:name="com.example.testfile.BootBroadcastReceiver" >
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
        <category android:name="android.intent.category.LAUNCHER" />
   </intent-filter>
</receiver>

Add the code for broadcast reception BootBroadcastReceiver.java, such as

package com.example.testfile;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;

public class BootBroadcastReceiver extends BroadcastReceiver{
    private static final String TAG = "sjft";

    public static final String EXTRA_VOLUME_STATE =
            "android.os.storage.extra.VOLUME_STATE";

    public static final int STATE_UNMOUNTED = 0;
    public static final int STATE_CHECKING = 1;
    public static final int STATE_MOUNTED = 2;
    public static final int STATE_MOUNTED_READ_ONLY = 3;
    public static final int STATE_FORMATTING = 4;
    public static final int STATE_EJECTING = 5;
    public static final int STATE_UNMOUNTABLE = 6;
    public static final int STATE_REMOVED = 7;
    public static final int STATE_BAD_REMOVAL = 8;

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String action = intent.getAction();
        if (action.equals("android.intent.action.PACKAGE_REPLACED")){
            String packageName = intent.getData().getSchemeSpecificPart();
            Log.v(TAG,"BootBroadcastReceiver packageName:"+packageName);
            if(context.getPackageName().equals(packageName)){
                Intent launchIntent = new Intent(context, MainActivity.class);//Restart the app 
                //If you don’t want to write the startup Activity, you can also get the default startup Activity by the following method 
                //Intent launchIntent = context.getPackageManager().getLaunchIntentForPackage(packageName);
                launchIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(launchIntent);
            }
        } else if (action.equals("android.intent.action.BOOT_COMPLETED")){
            String packageName = intent.getData().getSchemeSpecificPart();
            Log.v(TAG,"BootBroadcastReceiver packageName:"+packageName);
            if(context.getPackageName().equals(packageName)){
                Intent launchIntent = new Intent(context, MainActivity.class);//Restart the app 
                //If you don’t want to write the startup Activity, you can also get the default startup Activity by the following method 
                //Intent launchIntent = context.getPackageManager().getLaunchIntentForPackage(packageName);
                launchIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(launchIntent);
            }
        } 
    }
}

app system signature (signature file)
start app once

8.1.2. Launcher¶

Delete or not compile the Launcher application in the SDK

Add the following content to the first activity started in AndroidManifest.xml in the application source code

<intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

9. Modification of the default language¶

The language support list can be viewed in build/target/product/languages_full.mk.

9.1. Temporary modification method¶

System readable and writable

adb shell setprop persist.sys.root_access 3
adb root
adb remount

Modify the value of ro.product.locale in the /system/build.prop file (Android10 and above: /vendor/build.prop)
- en-US: English
- zh-CN: Chinese
System restart
```
adb shell reboot
```

9.2. Code modification method¶

Modify the value of PRODUCT_LOCALES in build/target/product/full_base.mk
- Chinese
```
PRODUCT_LOCALES := zh_CN
```

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

10. Modification of the default time zone¶

The time zone support list can be viewed in frameworks/base/packages/SettingsLib/res/xml/timezones.xml.

10.1. Temporary modification method¶

System readable and writable

adb shell setprop persist.sys.root_access 3
adb root
adb remount

Modify the value of persist.sys.timezone in the /system/build.prop file (Android10 and above: /vendor/build.prop)
- Asia/Shanghai：UTC+8
System restart
```
adb shell reboot
```

10.2. Code modification method¶

Android7.1/Android10
- In the file device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop, modify the value of persist.sys.timezone
  - Asia/Shanghai：UTC+8
Android11 and above
- Add the following content in the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file:
```
PRODUCT_PROPERTY_OVERRIDES += persist.sys.timezone=Asia/Shanghai
```

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

11. Default ROOT¶

11.1. Temporary modification method¶

adb shell setprop persist.sys.root_access 3

11.2. Code modification method¶

Android7.1/Android10.0
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
```
persist.sys.root_access=3
```
Android11 and above
- Add the following content in the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file:
```
PRODUCT_PROPERTY_OVERRIDES += persist.sys.root_access=3
```

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

12. The default system time is 24 hours¶

12.1. Code modification method¶

diff --git a/frameworks/base/packages/SettingsProvider/res/values/defaults.xml b/frameworks/base/packages/SettingsProvider/res/values/defaults.xml
index f95ecc6535..06055dba7b 100644
--- a/frameworks/base/packages/SettingsProvider/res/values/defaults.xml
+++ b/frameworks/base/packages/SettingsProvider/res/values/defaults.xml
@@ -244,4 +244,6 @@
 
     <!-- should show the screenshot button default -->
     <integer name="def_screenshot_button_show">0</integer>
+<!-- value 12/24/null corresponds to setting 12/24/auto -->
+    <string name="def_time_12_24" translatable="false">24</string>
 </resources>
diff --git a/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java b/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
index b3ff9d08a8..ebdd5d3637 100644
--- a/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
+++ b/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
@@ -2261,6 +2261,9 @@ class DatabaseHelper extends SQLiteOpenHelper {
    private void loadSystemSettings(SQLiteDatabase db) {
                                     ......
+            
+            loadStringSetting(stmt, Settings.System.TIME_12_24,
+                    R.string.def_time_12_24);

13. Open network ADB by default¶

13.1. Temporary modification method¶

13.1.1. Way one¶

Android7.1

adb shell setprop persist.internet.adb.enable 1

Android10/Android11/Android12

adb shell setprop persist.internet_adb_enable 1

13.1.2. Way two¶

Open “Developer Options”
Open ADB over network

Settings–>Developer options–>ADB over network

13.2. Code modification method¶

Android7.1/Android10
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
```
persist.internet.adb.enable=1
```
Android10
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
```
persist.internet_adb_enable=1
```
Android11/Android12
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file, add the following content:
```
PRODUCT_PROPERTY_OVERRIDES += persist.internet_adb_enable=1
```

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

14. The default setting of OTG USB3.0 is devices mode¶

14.1. Temporary modification method¶

adb shell setprop persist.usb.mode 2

14.2. Code modification method¶

Android7.1/Android10
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
```
persist.usb.mode=2
```
Android11/Android12
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file, add the following content:
```
PRODUCT_PROPERTY_OVERRIDES += persist.usb.mode=otg
```

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

15. Turn on or turn off the installation of unknown apps¶

15.1. Code modification method¶

15.1.1. Android 7.1¶

In the frameworks/base/packages/SettingsProvider/res/values/defaults.xml file, modify the value of def_install_non_market_apps.

false : Close
true : Open

15.1.2. Android10 and above¶

In Android10, the permanent authorization option of “Allow Unknown Sources” to install applications has been deleted. The switch is no longer found in the system settings. Google will modify the permanent authorization to a separate authorization each time. When the user installs a third party each time The source of the Android software requires manual confirmation of the software permissions.

16. Turn touch sound on or off¶

16.1. Code modification method¶

In the frameworks/base/packages/SettingsProvider/res/values/defaults.xml file, modify the value of def_sound_effects_enabled.

false : Close
true : Open

17. Modify the desktop layout¶

17.1. Code modification method¶

After the device is turned on, the program shortcuts, small plug-ins, shortcut navigation bar (HotSeat) and folder modification methods that are loaded on the desktop by default.

For details, please refer to the post of the open source community。

18. Configure USB camera front or rear¶

The default is front.

18.1. Temporary modification method¶

Front

adb shell setprop persist.sys.uvc.facing front

Back

adb shell setprop persist.sys.uvc.facing back

18.2. Code modification method¶

Android7.1/Android10
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
  - Front
```
persist.sys.uvc.facing=front
```
  - Back
```
persist.sys.uvc.facing=back
```

Android11/Android12

In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file, add the following content:

Front

PRODUCT_PROPERTY_OVERRIDES += persist.sys.uvc.facing=front

Back

PRODUCT_PROPERTY_OVERRIDES += persist.sys.uvc.facing=back

Delete build.prop in the out directory

rm out/target/product/PRODUCT_TYPE/obj/ETC/system_build_prop_intermediates/build.prop

19. Configure 4K UI¶

19.1. Code modification method：¶

19.1.1. Platform(RK3399/RK3568)¶

Android7.1
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/system.prop file, add the following content:
```
persist.sys.framebuffer.main=3840x2160@25
```
Android10.0 and above
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file, add the following content:
```
PRODUCT_PROPERTY_OVERRIDES += persist.vendor.framebuffer.main=3840x2160@25
```

NOTE: The 4K UI occupies a large amount of system resources and supports a maximum of about 4K25Hz. You are not recommended to use the 4K UI. If you just want to play it 4K video or view 4K pictures, it can not need to configure 4K UI, the system’s default video player and picture browser can support.

19.1.2. Platform(RK3588)¶

Android12.0 and above
- In the device/rockchip/CPU_TYPE/PRODUCT_TYPE/PRODUCT_TYPE.mk file, add the following content:
```
PRODUCT_PROPERTY_OVERRIDES += persist.vendor.framebuffer.main=3840x2160@60
```

NOTE:RK3588 has strong performance and supports 4K UI at 60Hz.