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How do I uncompress an initrd image?

How do I uncompress an initrd image?

How to extract the contents of an initrd. img file?

  1. Step 1: Copy the initrd.
  2. Step 2: initrd.
  3. Step 3: The output of the above gunzip command is a file named ‘ initrd ‘ located in /tmp/initrd folder.
  4. Step 4: Create a folder where you prefer to save and later modify the contents of initrd .
  5. Resources:

How do you repack an initrd image?

To keep the same folder hierarchy three steps are needed:

  1. Make CPIO file system archive with simple -o option without newc format in created before eg. base folder:
  2. Make proper archive with newc format containing kernel/x86/microcode/GenuineIntel.bin:
  3. Add gzipped filesystem archive to the proper new_initrd.img:

How do I view modify and recreate initrd IMG?

View, Modify and Recreate initrd.img

  1. Decompress the initrd. img.
  2. Extract the cpio archive.
  3. View the contents and make the required changes.
  4. Pack the cpio archive.
  5. Compress the cpio archive using any of the compression method need not to be same as original compression method.

What is initrd IMG?

initrd provides the capability to load a RAM disk by the boot loader. This RAM disk can then be mounted as the root file system and programs can be run from it. The initrd files are usually in /boot directory, named /boot/initrd. img-kversion with a /initrd.

How do I extract Vmlinuz?

Extracting the Linux kernel image (vmlinuz) You will be able to find the extract-linux script at /usr/src/linux-headers-$(uname -r)/scripts/extract-vmlinux . You will be able to find the extract-linux script at /usr/src/kernels/$(uname -r)/scripts/extract-vmlinux .

What is ZCAT used for in Linux?

Zcat is a command line utility for viewing the contents of a compressed file without literally uncompressing it. It expands a compressed file to standard output allowing you to have a look at its contents. In addition, zcat is identical to running gunzip -c command.

How do you repack an initrd?

How to modify and repack an initrd image file

  1. Create a temporary Directory.
  2. #mkdir /root/initrd. #cd /root/initrd.
  3. Then uncompress and extract the initrd.
  4. #zcat /boot/initrd-2.6.18-164.6.1.el5.img | cpio -idmv.
  5. Modify the initrd and repack the intrd as new image.
  6. # find .
  7. Create a temporary Directory.
  8. #mkdir /root/initrd.

How do I unzip a cpio file in Linux?

cpio command in Linux with Examples

  1. Copy-out Mode: Copy files named in name-list to the archive. Syntax: cpio -o < name-list > archive.
  2. Copy-in Mode: Extract files from the archive. Syntax: cpio -i < archive.
  3. Copy-pass Mode: Copy files named in name-list to destination-directory. Syntax:

What is the purpose of Systemd?

Its main aim is to unify service configuration and behavior across Linux distributions; systemd’s primary component is a “system and service manager”—an init system used to bootstrap user space and manage user processes.

What is the purpose of initrd?

The Linux initial RAM disk (initrd) is a temporary root file system that is mounted during system boot to support the two-state boot process. The initrd contains various executables and drivers that permit the real root file system to be mounted, after which the initrd RAM disk is unmounted and its memory freed.

What is vmlinuz in Linux?

vmlinuz is the name of the Linux kernel executable. vmlinuz is a compressed Linux kernel, and it is bootable. Bootable means that it is capable of loading the operating system into memory so that the computer becomes usable and application programs can be run.

What is bzImage in Linux?

The bzImage is the compressed kernel image created with command ‘make bzImage’ during kernel compile. It important to note that bzImage is not compressed with bzip2 !! The name bz in bzImage is misleading!! It stands for “Big Zimage”. The “b” in bzImage is “big”.