Problem mounting encrypted Windows install in RE.

Hello,

Now bear with me here, this is likely going to be a long post.

The title represents the step I am currently stuck at in a long chain of steps I've taken to solve quite a minute issue(in some peoples minds) which is that I am trying to get rid of the 256KB limit on file sizes imposed by Windows 7 on the logon screen background.

Yes, I'm trying to replace the generic Windows 7 logon background image with a high-res custom one.

First, a bit of background.

I decided to redo the whole system of mine a while back. Reinstalling Windows 7 Professional, encrypting it and then alongside it, installing a linux distro as well.

The process is done and I have Win7 encrypted with Veracrypt(FDE) and Ubuntu MATE alongside it, encypted with LUKS. Both systems are booted via GRUB2 of which I had to do a little hack since VeraCrypt's bootloader needs to be launched before the Windows one.

Systems work fine, all customized in Linux and GRUB, now however I wanted to do it in Windows too. A little OCD'ness in me. (Login screens, bootup screens, configurations and such) Whilst also implementing full-scale security.

To achieve the end goal I found some info through DuckDuckGo(Google Proxy) on this website: Custom Windows 7 Login/Lock Background, with 256kB limit removal - Tech Chatter - Open Carnage

The lads there instructed on how to remove the imposed limit in the binary file by replacing 2 bytes with no-ops. Said and done.

Now the next step is where the process for me has hanged. I must now replace said file in system32, named authui.dll with the modified one. However since Windows doesn't really allow to do so with files in use, you have to launch the recovery environment within which you can do so via the shell, before the system is launched and locks the files down due to usage.

Now the problem arrives in the point where I have to actually move into the filesystem on my main drive C. Which boots up fine and is mounted properly via the regular boot-up process since VeraCrypt got nicely integrated into it.
However in the RE, once the system files are loaded, the shell prompt informs me that it doesn't recognize the filesystem where the main installation is sitting at. Now I believe this is because after the system files are loaded, the initial booted kernel hands control over to the new one which was loaded into a virtual drive X and along with it, VeraCrypt isn't present among the default drivers, causing it to lose the ability to recognize anything on the encrypted drive. That's my guess.
I haven't yet figured out how to launch the driver the way it does in the normal boot-up. And then how to mount the filesystem(if it is even done the way it's done in Linux).

Anyone have an idea how to achieve this? I've tried googling(ducking) it but haven't really found anyone with such a specific problem.

I'm talking about the veracrypt.sys file(I assume this is what I need). However manually loading the driver through the "load driver" option in the RE, comes up with an error that says something along the lines of that "This driver doesn't describe any hardware..." etc. on your system.

Does it require a .inf file as well, or what am I missing here?

Thanks.

Welcome,

Just a thought, why not "decrypt" the Windows drive and then boot to Linux to replace the file.

That was an afterthought I had myself actually.

But thing is though, I've never done it before. Would actually prefer not to either.

And it'd be more interesting to actually know how to manually decrypt and mount the filesystem.

But if there's no other way, I'll probably do it that way later on. (Currently encrypting a 3rd TB HDD drive that's going to take the entire night)

Yeah, eventually decrypted the drive and re-encrypted it to make the change.

End result was worth it though. High-res logon screen ftw :).