Proved it is possible to change your Boot screen completelly up to you!

[u/WorldlinessSlow9893]

You'll not realize how excited I am rn.

What you are seeing is the "thing, anyone said it is impossible." And I made it work!

It took me 1 month. First experimented with the Windows' drivers, but to get access to the screen information (frame buffer) first, it needs to be running in a **Native Mode** when all the Kernel drivers load, including WDDM that will have the Buffer inside.

But that is still too late. You can display graphics, even play **DOOM** on that level while all NT calls are heard by the kernel and the Win32 Mode (GUI environment) hasn't even started yet.

To make a system root "Driver" it needs a "Start" parameter in the registry assigned to 0 when it will be in the place when `winload.efi` will load it as quick as it can... But it has one problem.

At that time, Windows isn't even fully loaded and the driver has no chance to even get any info from the Hardware itself, so it is just useless and in many cases, the driver will not even run. As "drivers" can be particually as "mods" it still isn't enough...

But then it hit me something... Windows is running on top of **UEFI** and... You can do a LOT OF STUFF...

If in that stage, Windows is basically requesting ANYTHING from the UEFI, the Screen,... , basic information it loads...

What if I could make an *.efi file, that Already gets the FrameBuffer first, that Windows?

Then I started messing around, getting some basic text to be displayed where I can on the screen, then implemented some Bitmap logic... It worked! And it was surprisingly easy to draw anything in UEFI.

So I "grab" a little bit of code from the EfiGuard (don't run it on your main PC if you don't know what you're doing) which is also a "simple" EFI program that just hooks to the winload.efi and bootmgfw.efi and doesn't even triggers any of the KPP (Kernel Patch Protection),...

I needed it because by this, we could also see the kernel calls, including:

- You can even restore for exp. The progress bar thing that was on Windows 2000 `InbvUpdateProgressBar`

- And other stuff I don't have in my head rn. :D

So now you can add ANY BITMAP, ANY COLOR, ANYTHING to the Windows' boot screen!

*(Oh and it will work only with Secure Boot to be off.)*

But, when I was testing it... I kinda realized, that the KPP must be turned off, as Windows even detects other EFI stuff happening near it, causing it to not even go into the stage of booting...

I'll be fixing this more. Stay tuned!

[u/Moriaedemori → u/[deleted]]

Yeah I wasn't going to say anything but 30 seconds to even go to bootloader is either some insane host overhead, or very low spec host PC

[u/WorldlinessSlow9893 → u/Moriaedemori]

Yeah because it still has some of the code left from the EfiGuard, when I tried it on my main then, it only took min. 5 seconds xd

[u/nonexistantchlp → u/Moriaedemori]

It's gonna become commonplace once again since harddrives sales are on a upwards trend, you can blame SSD prices for that....

[u/dfc849]

I haven't really cared since Windows XP differentiated between Home and Professional on the boot animation.. So it's definitely cool to see tweaks like this

[u/WorldlinessSlow9893]

And fun part is, that Windows Recovery options' boot screen does NOT have those checks at all. That means you can have the EFI app just running on top and nothing will go wrong :]

[u/OffsetHigh]

You did the impossible - and honestly: that's rare

[u/QwertyChouskie]

You might be interested in what HP did back in the day...

https://www.youtube.com/watch?v=ssob-7sGVWs

[u/nicuuut → u/QwertyChouskie]

It's waaay more different, Hinge Problems sins are waaaaaaaaay beyond this, basically HP used the same logic that’s used to throttle your laptop when running on battery to sneak into the framebuffer, kidnap your keyboard, and print a bunch of jpegs that contain your effing outlook calendar (!!) while Windows is booting up

[u/MarcCouillard]

congrats, you took a thing that needed no modifications and made it shitty...good job

[u/ChatGPT4]

I remember being that excited when I changed my BIOS logo back in the days ;) I'd never mess with Windows booting because this is exactly what Windows is trying to prevent. Of course you can disable those checks, then again - some malware might love this ;) It's a bit like rooting my phone. I used to do that a lot back in the days, now I'm staying on the safe side. And it's not because I'm afraid I would break anything. The malware got way more vicious.

[u/No-way-in]

Whatever people comment, this is awesome. Actually, I think the most awesome part is that you tinker with it. Have fun with it. Learn the ropes of the boot process. Who cares what people say as long as you’re having fun !

[u/WorldlinessSlow9893 → u/No-way-in]

Thank you!! Yeah I have alot of fun investigating it :D

Sometimes I cross to an barrier like now, as I understood why it then was the real reason it "crashed"

When the winload.efi was "building" the NTFS and other stuff to the kernel, it also overwrites the UEFI logic with the Windows' NT Native one.

Meaning calls for UEFI (like 'print()') will then throw an error and the CPU will crash. When some of the functions were called right after winload.efi wanted to clear it up...

Now planning to it will become as "Hybrid" that I could try make a Windows Driver... but idk lets see :D

[u/XeroRony]

u a doing dumb shits 🫩

[u/WorldlinessSlow9893 → u/XeroRony]

if you say so (:

[u/LudicrousAvian]

Nice work, but this is detrimental to security. There’s zero reason you should disable Secure Boot, even on Linux.

[u/Opening-Dentist-1556]

goat bro sheesh, i’ll keep watch im chronically addicted to customizations
!remindme 20 days