[Android Software/Hacking General [Developers Only]] chocolote4444:
Welcome. Today I am going to teach you how to modify your android boot logo!

Modify at your own risk! I strongly recommend that you do not try this. But if your going to attempt this, make a BACKUP! I will explain the backup process down the page!

This method has been tested on the Galaxy S6. I RECOMMEND you do NOT attempt this method on any other smartphone other than the S6!

I own a Samsung Galaxy S6 [SDK21 ARM64] and my carrier is Straighttalk. This method might possibly work with the newer Android smartphones. In other words, attempting to do my method will probably not work with androids running 4.4.2 or lower. I will first explain why.

According to what I researched, there is a file in the root directory of the Android system that contains a file called "initlogo.rle". That is your boot logo. Older Android phones had this. The .rle is a bitmap extension and cannot be edited with Android. Actually, let me rephrase that, the .rle COULD MAYBE possibly be edited if you were to download the right tools off of the Play Store but computers can identify .rle as a bitmap very easily and can be opened. Windows computers can open .rle according to what I researched.

The initlogo.rle is also part of the boot.img. The boot.img contains the kernel and the boot files (like init.rc), that are necessary for the phone to boot up. Modifying your boot.img requires a computer. You can't just replace the initlogo.rle with another one. To make changes to a boot.img, you need to unpack the ramdisk, replace or modify the files, repack, and THEN flash the modified boot.img to make the changes.

Newer Android smartphones don't have initlogo.rle. Or at least MINE doesn't. Instead, I had to search for my boot logo which took my quite a while. After searching deep into the android system and messing around with the files, I came accross PARAM.

If you were to go in the /dev/block/platform directory, you would come accross a file called PARAM. Mine was in the directory /dev/block/platform/15577000.ufs/by-name. Inside that directory is basically the whole system. You will find files like BOOT, EFS, OTA and all that. You will also notice that all those files look empty. They all show 0.00B. I don't know exactly why that is, but they aren't really empty files.

My official boot logo was in the file "PARAM". What I did was copied it to my internal directory and attempted to extract it. After trying different extensions, I founded out that .tar is the correct extension. So to extract it, I renamed "PARAM", to "PARAM.tar". After doing that, you will be able to actually extracted it and be left with files with .jpg. Basically pictures inside it. I used root browser. :good:

Inside, you should find "logo.jpg". And whatta ya know! It's your boot logo!

I used PicArt to create a custom boot logo. It is a really great app! You can get it off the Play Store. Then I renamed it to logo.jpg and replaced the original logo.jpg with my newer one. Make sure it is named "logo.jpg" or there will be errors!

Now the last step is to archive the files through .tar format. I used root browser to do that. To correctly archive the files, multi-select the .jpg files. In other words, DON'T SELECT THE "PARAM" FOLDER!!!

When archiving the files, use LZMA compression option along with tar.(Look for that with root browser). This will not compress the files as much which will reduce the risk of errors.

Once it's archived, rename the new archive file to just "PARAM".

LAST STEP! Before overwriting your PARAM, copy your modified PARAM into the /system folder and set the correct attributes (PERMISSIONS) to -rwxrwxrwx. Now you are ready. Copy "PARAM" to the same director where you originally got your unmodified PARAM file. It will ask you if you want to overwrite. Say yes.

I was now introduced with a different boot logo. My phone never got bricked during the process. However, with Android, ANYTHING can happen, so I will give you some advice. If you have a custom recovery, you can easily restore PARAM. Make a copy of your original PARAM and put it in your internal directory. If something ever goes wrong, you can use the file manager (like with TeamWin) and replace the currupt PARAM with your backup PARAM. Then set the permissions to -rwxrwxrwx or 0777

I strongly recommend that you do not try this. Yes, I took the risk and was able to safely change my boot logo. However, not all Android devices are the same so be very careful if you are attempting to do this one an Android device OTHER than the Galaxy S6.

Leave comments if you have any questions! :p