[Fire HD 8 and HD 10 General] DragonFire1024:
Part 2: Change your lock screen wallpapers

This guide will teach you how to change all of the stock FireOS wallpapers. This is much easier than activating Daydreams and you don't need Java or Apktool to make the edits.

This guide is mainly for individuals who want to or already disabled/uninstalled Amazon Photos. When you disable or uninstall Amazon Photos, you lose the ability to change your lock screen wallpapers. This guide will work for both the Fire 7 and HD 10.

Requirements:

- ROOTED Fire 7 or HD 10

- 7-Zip

- ADB insecure

- Your choice of any 7 wallpapers

- Windows PC with ADB

Instructions:

IMPORTANT: Make a copy of your SystemUI.apk at /system/priv-app/SystemUI and place it somewhere on your PC in case you have an unfavorable result, you won't have to reset your device.

1. Download and install 7-zip.

2. First we need to get a copy of your SystemUI. Plug your tablet into your PC, making sure ADB debugging is enabled in the developers menu. Open an ADB window on your PC and type the command below (the actions of moving the SystemUi.apk around should only be done via ADB. Never copy and past an APK from one device to another if you intend on editing it.)

adb pull /system/priv-app/SystemUI/SystemUI.apk

3. Running the above command will have resulted in making a copy of your SystemUI.apk and then placed it on your PC, into the same folder as ADB.

4. Create a folder on your desktop for the 7 wallpapers you desire. You can pick 7 different ones, or use the same wallpaper 7 times, but you can't choose any more or any less of a quantity. Putting anymore or less in the SystemUI will cause the tablet to bootloop. I have a collection of about 200 stock Android wallpapers from the first version, all the way to Nougat. It doesn't matter what size they are because you'll be resizing them anyways.

5. Once you've chosen your wallpapers, you'll have to resize them. For this guide I will be using Microsoft Paint. Navigate to the folder containing your new wallpapers and open the first one in Paint. Click the 'Resize' button at the top left of the screen, select Pixels and make sure the 'maintain aspect ratio' box is UNCHECKED. Your wallpaper MUST be the same size/resolution as Amazon's. Enter the values as listed and pictured below:

Horizontal: 1920
Vertical: 1200

6. Save the wallpaper as a .jpg. The name doesn't matter right now because we will be renaming them. If you are going to use 7 different wallpapers, you need to make a copy of the wallpaper you just resized. Open it in paint and again click resize, select Pixels and make sure 'maintain aspect ratio' is UNCHECKED. Reverse the dimensions:

Horizontal: 1200
Vertical: 1920

7. If you want to keep the same wallpaper on your lock screen all the time, repeat the above step with copies of the same wallpaper. Regardless if you use the same ones or different ones, you will have 14 wallpapers in the folder when done.

8. Navigate back to your ADB folder and locate SystemUI.apk. Right click on it and select the '7-Zip' option then 'open archive'. DO NOT UNZIP, EXTRACT OR DECOMPILE THE APK! Resize the window so you have a good amount of space to open the wallpaper folder we just made. Place the windows next to each other.

9. In the 7-zip, SystemUI archive window, double click on the 'res' folder then locate and double click the 'raw-hdpi-v4' folder. This is the location of the Amazon's default lock screen wallpapers. In your custom, wallpaper folder, you need to rename each wallpaper to match the names of Amazon's. It's important you do this step and that the names match. Otherwise when you reinstall the SystemUI, it will crash.

10. When you're done, in your custom wallpaper folder, click on 'Edit' a the top and 'select all'. Click on any of the wallpapers but don't let go! Start to drag them over to the 7-zip SystemUI window. Make sure you have all of them, then let go. When the box pops up asking you if you want to overwrite the other wallpapers just click yes. Close both windows and open an ADB window again.

11. Download and install ADB Insecure from the link at the beginning of this post. Open it and grant it root access if you don't have SuperSU set to automatic. Check the box to put ADB into insecure mode. In the ADB window, type the following commands, pressing enter after each one.

adb remount
adb push SystemUI.apk /system/priv-app/SystemUI/SystemUI.apk
adb reboot

12. That's all. If successful, your tablet will reboot and your custom lock screen wallpaper(s) should appear. If unsuccessful, your tablet will reboot, but with no SystemUI active. I'll write a small guide on recovering from a SystemUI crash without reflashing firmware if anyone has a problem. Until then enjoy your wallpapers. Just remember you have to repeat this guide each time you want to change them. Until I can figure out how Amazon Photos has such control over the lock screen, this is the only way to change your lock screen wallpapers if you uninstall Amazon Photos. Thank you for following everyone!