Mods Need to change boot image on rooted tablet [Root only]

[chasembrown]

For my job, I have been tasked to change the default boot splash image of a KingPad K100 Tablet to an image of the companies logo. I have done a couple of hours of research but haven't turned up many results. Tutorials I've found discussing changing the boot image are outdated, and all of the newer ones only refer to boot animations.
I have also found apps but they only seem to support pre-made animations.

1) How do I make a custom boot image?

2) How do I install said boot image?

A things I believe are noteworthy: This tablet is set up as a dedicated media player so it has no network access (wired or wireless). It can only be programmed by adding files to a USB, plugging it into the tablet, and installing from a file browser.

Any help is appreciated!

Info:
Kingpad K100 Tablet
Android version: 4.4.2
Kernel version: 3.10.33
Software version: V1.1.4

 

[scary alien]

Welcome to our AndroidForums, @chasembrown .

More important than root is if your device has an unlocked bootloader (i.e., so you can flash a new boot.img to your device).

If so, you should be able to use something like
[DEV][TOOL] Android Image Kitchen - Unpack/Repack Kernel Ramdisk [Win/Android/Linux] that osm0sis built to do parts of what you're asking.

The "picture image" (gotta be careful here using the word image here because there are two different contexts: one for a bootable image file/area on your device and the picture "image" that you want to change) is likely in the boot.img for your device, but is also not likely a simple .jpg or .png file (sometimes its in a rather arcane format that requires a separate image processing tool).

But first you have to determine if you have an unlocked bootloader and can pull the boot.img file off of your device.

What you're asking about/for is certainly not a trivial task if you don't have the knowledge and foundation for many of the concepts you're going to encounter along the way with this endeavor (I guess what I'm trying to say is that your company has asked a lot of/from you ).

 

[chasembrown]

Welcome to our AndroidForums, @chasembrown .

More important than root is if your device has an unlocked bootloader (i.e., so you can flash a new boot.img to your device).

If so, you should be able to use something like
[DEV][TOOL] Android Image Kitchen - Unpack/Repack Kernel Ramdisk [Win/Android/Linux] that osm0sis built to do parts of what you're asking.

The "picture image" (gotta be careful here using the word image here because there are two different contexts: one for a bootable image file/area on your device and the picture "image" that you want to change) is likely in the boot.img for your device, but is also not likely a simple .jpg or .png file (sometimes its in a rather arcane format that requires a separate image processing tool).

But first you have to determine if you have an unlocked bootloader and can pull the boot.img file off of your device.

What you're asking about/for is certainly not a trivial task if you don't have the knowledge and foundation for many of the concepts you're going to encounter along the way with this endeavor (I guess what I'm trying to say is that your company has asked a lot of/from you ).

Wow thank you for such a thoughtful response! This definitely seems much more involved than previously expected. The tablet's boot picture was already altered to our distributors logo upon purchase so I thought it wouldn't be too difficult. Currently trying to figure out if this tablet actually has an unlocked bootloader..

 

[scary alien]

Ah, maybe the distributors have a special tool/utility that allows them to update it...

If you have the fastboot utility handy and think you might have the fastboot USB drivers installed, then putting your device in fastboot/bootloader mode and invoking a fastboot getvar all command might reveal the bootloader lock status.

Sometimes the bootloader screen itself will show the lock status (device-dependent).

Sometimes the fastboot protocol is not supported for a device (again, device-dependent).

Since you are rooted, you will also need to know the partition layout with respect to where the boot partition is. This can be done a couple of ways:

- find / identify a "by-name" folder usually under the /dev/block/mmcblk0 hierarchy

- listed in the /cache/recovery/last_log file​

You'll need to know this in order to pull the current boot image off of your device so it can be examined and the picture/image file updated (replaced).

It is also possible to flash (overwrite) the boot image without having fastboot access, but that's not a preferred method (i.e., the fastboot method is safer).

FYI, this endeavor is a bit "risky", by the way , so I hope your bosses know this...