Download Windows Loader For Windows 7 32 - 64 Bit
Belen Varenhorst
I have Windows 8 pre-installed, and then I installed GRUB with Ubuntu. Ubuntu is not my thing, so now I want to remove it along with GRUB. From what I have learned, with UEFI, GRUB does not overwrite the windows bootloader in the EFI partition and is stored elsewhere. How would I remove GRUB and make my PC use the Windows bootloader instead? It should be noted that I created a separate /boot partition when installing Ubuntu.
Enter powershell into the windows search of the start menu. Look for a blue icon with the label "Windows PowerShell", right click on the that and select "Run as Administrator" within the context menu.
download windows loader for windows 7 32 - 64 bit
Download Windows Loader For Windows 7 32 - 64 Bit ✦ https://urllie.com/2zFIil
You can restore the Windows bootloader with a Windows 8/8.1 DVD. These instructions are inspired by Manindra Mehra's answer, but I expanded it with full working details (verified with a Windows 8.1 DVD).
Your DllMain function runs inside the loader lock, one of the few times the OS lets you run code while one of its internal locks is held. This means that you must be extra careful not to violate a lock hierarchy in your DllMain; otherwise, you are asking for a deadlock.
The loader lock is taken by any function that needs to access the list of DLLs loaded into the process. This includes functions like GetModuleHandle and GetModuleFileName. If your DllMain enters a critical section or waits on a synchronization object, and that critical section or synchronization object is owned by some code that is in turn waiting for the loader lock, you just created a deadlock:
Loader refers to the OS (module) loader.Loader Lock is a system lock used by the loader to synchronize calls to DllMain.This way, the loader ensures that initialization / cleanup tasks required by DLLs are performed in a thread-safe manner.
(...) the operating system has its own internal process-specific lock that sometimes is held while your code executes. This lock is acquired when DLLs are loaded into the process, and is therefore called the 'loader lock.' The DllMain function always executes under the loader lock; (...)
The other answers given here work great on MBR/BIOS systems, however if you're on a UEFI system like I am, bootsect will just write a semi-functional boot MBR over the GPT protective MBR and bootrec just gives an "Access denied" error message, and neither one has a functional option to fix a broken EFI system partition, which on a UEFI/GPT drive is what contains the bootloader that used to be stored in the MBR. There's unfortunately almost no up-to-date guides on fixing the UEFI Windows Boot Manager (almost all of them just say to run the graphical Startup Repair utility, but that doesn't fix the problem in all cases), but I finally found the correct solution buried in this article, which requires the use of the bcdboot command instead:
(Optional) If you are not currently dual booting and want to fully clean the ESP before writing a new bootloader, run format N: /FS:FAT32 to reformat it as FAT32. This is probably not necessary under normal circumstances, however, as bcdboot seems to do a good job of cleaning things up itself. Especially do not do this if you have a Linux distro on another partition or else you'll have to reinstall GRUB as well once you're done with this. Also note that the following steps should not affect an EFI GRUB install as long as you do not otherwise delete GRUB's existing directory on the ESP.
Finally, write the new bootloader to the partition with bcdboot C:\windows /s N: /f UEFI. This command rebuilds a new UEFI-compatible bootloader on the ESP mounted at N: using the Windows installation mounted at C:\windows. Once it's done, you can verify the new bootloader was written by running dir N:\EFI, where you should see a Microsoft directory containing the new Windows Boot Manager as well as a boot directory containing the fallback bootloader (along with other directories for any other bootloaders you have installed, such as GRUB for Linux).
In addition to that, how should I add Arch to the Windows Bootloader, as I'm unsure of what I need to do with bcdedit, or if EasyBCD 2.2's compatibility with EFI is confirmed. Also, if anyone has any good program recommendations in lieu of EasyBCD, it would be appreciated.
A loader is code that prepares other code for execution. Loaders take data
corresponding to a program or library and prepare it to be read, modified, and/or executed. This preparation process typically involves steps such as parsing a file containing the code to be run, metadata about that code, and other relevant bits of information such as the external services it might need from other parts of the operating system. Additionally, things like resolving external dependencies - or other, external bits of code the bit being prepared will rely upon, setting memory protections appropriately, and perhaps updating references (if the code is not position independent) will happen here.
Nearly all modern consumer-facing operating systems contain loaders. Loading occurs during the initialization of a process (when the primary application image is loaded), and also may occur in an ad-hoc fashion throughout program execution, as dynamic libraries (to include .dlls, .dylibs, and .sos, for example) are loaded and unloaded.
In the context of things like threat emulation, there is a strong desire to model trends present within the modern malware ecosystem - including the ability to operate in memory only. This presents a bit of a challenge: in Windows, for example, the operating system's built-in loader
only accepts binary files on disk. What we desire is a reflective loader
that will perform some of the same kinds of preparations that the native operating system's loader would handle, but without the requirement that the loaded binary reside on disk (note that some operating systems, such as MacOS, have facilities for executing directly in-memory natively).
The reflective_loadlibrary function accepts three arguments. First, it accepts
a loader_ctx, which contains a pointer to a structure we will use to manage contextual information that the loader will need as we implement it. Next, it accepts a buffer and its corresponding size, which represent the module that we wish to load. The function returns a LoaderStatus, which is a type we've created to help provide status results around success or failure as loader development progresses.
The Portable Executable (PE) format is a file format for executables, DLLs, Drivers, and some more exotic kinds of files on 32- and 64-bit versions of Windows. It contains all the information Windows needs to load and execute the specified module. Since we're re-implementing some of the Windows loader's functionality, we'll also need to parse PE files during the course of loading and executing.
For robustness, we'll want to verify that the buffer that our reflective loader receives is actually a PE file. A simple validation technique is to check that (a) the e_magic value is correct, and (b) that the RVA of the NT headers resides within the bounds of our buffer. The code snippet below illustrates how we might perform these checks.
The first field is a bit poorly named, as it is actually an RVA, coupled with a size. We will visit quite a few of these table entries as we progress through the loader development sections that follow.
While many allocator APIs exist in Windows, some special considerations must be applied to requesting memory for our loader. In particular, we have some special alignment and protection requirements (in general) that we will need to adhere to in order to ensure that our program will perform properly once loaded.
To keep things simple, we will start with VirtualAlloc, but keep in mind that other options exist, and may have different implications in terms of how our memory footprint looks forensically. So how much space should we get? In order to obtain that information, we should refer back to the IMAGE_OPTIONAL_HEADER structure from the last section, in particular, the SizeOfImage field. Thus, we can update our loader method as follows:
You can install the Windows Vista / 2008 / 7 bootloader onto a Windows XP machine and dual-boot Windows XP and Windows 2008 / 7 from the VHD (I don't believe Vista has VHD boot support). I'm doing this on my main laptop computer right now. The easiest way to do it is simply to install Windows 2008 / 7 into a VHD, and you get the bootloader "for free" during the install.
Such a limitation is not enforced by the Linux kernel, but can depend on which boot loader is used and/or how the boot loader is configured. The Windows limitation should be considered if the user wishes to boot Windows and Linux from the same disk, since installation procedure of boot loader depends on the firmware type and disk partitioning configuration. In case where Windows and Linux dual boot from the same disk, it is advisable to follow the method used by Windows, ie. either go for UEFI/GPT boot or BIOS/MBR boot. See for more information.
Most of the linux bootloaders installed for one firmware type cannot launch or chainload bootloaders of the other firmware type. That is, if Arch is installed in UEFI/GPT or UEFI/MBR mode in one disk and Windows is installed in BIOS/MBR mode in another disk, the UEFI bootloader used by Arch cannot chainload the BIOS installed Windows in the other disk. Similarly if Arch is installed in BIOS/MBR or BIOS/GPT mode in one disk and Windows is installed in UEFI/GPT in another disk , the BIOS bootloader used by Arch cannot chainload UEFI installed Windows in the other disk.
The only exceptions to this are GRUB in Apple Macs in which GRUB in UEFI mode can boot BIOS installed OS via appleloader command (does not work in non-Apple systems), and rEFInd which technically supports booting legacy BIOS OS from UEFI systems, but does not always work in non-Apple UEFI systems as per its author Rod Smith.
However if Arch is installed in BIOS/GPT in one disk and Windows is installed in BIOS/MBR mode in another disk, then the BIOS boot loader used by Arch CAN boot the Windows in the other disk, if the boot loader itself has the ability to chainload from another disk.
760c119bf3