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19 views

Initramfs not reading new configuration/scripts

I am trying to add some custom initramfs scripts to /etc/initramfs-tools/scripts/init-bottom/. However, these are not executed at next boot, after having rebuilt with # update-initramfs -u In fact, ...
2
votes
1answer
64 views

initrd and initramfs confusions

I read from arch wiki: In case your root filesystem is on LVM, you will need to enable the appropriate mkinitcpio hooks, otherwise your system might not boot. However, both my initrd and ...
0
votes
0answers
39 views

trap signal in bash initramfs fails to work

inside /init bash script executed by the kernel in initramfs.img i need to send a signal to drop me to a rescue shell, so i have trap "exec /bin/bash" SIGINT but ctrl+C isn't effective. First why ...
2
votes
1answer
274 views

Can't mount squashfs loop during initramfs

I am trying to mount a squashfs file during initramfs. I have included loop and squashfs modules. Currently using mount /foo.squashfs /mountpoint or mount -t squashfs -o loop /foo.squashfs /...
1
vote
2answers
212 views

how to know the right size of /boot

for now /boot on our linux machines is /dev/sda1 497M 157M 340M 32% /boot we want to create a new linux redhat template and I have the feeling that /boot size is too small for ...
0
votes
1answer
54 views

kernel sysfs doesn't recognize storage kobjects [closed]

I am using ubuntu kernel 4.xx with corresponding ubuntu initrd.img, and it works. But, I want to use a custom initramfs inspired by lfs (linux from scratch) initramfs. The kernel extracts, and runs ...
1
vote
0answers
197 views

Why can't dd write to /dev/ram0 on Core Linux?

I created an ext2 file-system on /dev/ram0 ramdisk, and mounted it at /mnt/ram. mkdir /mnt/ram mkext2fs /dev/ram0 sudo mount /dev/ram0 /mnt/ram -o rw Reading from ramdisk with dd works. dd if=/dev/...
0
votes
0answers
161 views

How to find modules used in initrd?

Is there a way to see all the kernel modules/drivers put in the initrd/intramfs?
0
votes
0answers
341 views

Accessing initramfs-tools features in Yocto generated initramfs image

I would like to load a few kernel modules, and activate framebuffer access prior to Plymouth launch. This is normally done using /etc/initramfs-tools directory provided with the initramfs-tools. ...
2
votes
2answers
447 views

Why kernel cannot do the initrd/initramfs job itself? [closed]

Currently I am learning about linux booting process.Here i noticed that the initrd will create temporary root file system that includes drivers(LVM, NFS, etc) which are required by kernel.After that ...
5
votes
0answers
431 views

How to combine linux kernel and initrd without compiling?

I know that it's possible to extract from a linux kernel the embedded initramfs cpio. I want to know if the reverse operation is possible; i.e., given both a compiled kernel and initramfs archive, how ...
1
vote
2answers
2k views

Debian system doesn't mount or find /sbin/init during boot

I'm getting the dreaded "target filesystem doesn't have requested /sbin/init", am getting dropped into initramfs busybox prompt, and am unable to boot. This is after upgrading to the latest 4.9.0-3 ...
2
votes
0answers
186 views

Using an initrd/initramfs as the root filesystem

In Android, the initial RAM disk stays mounted throughout the entirety of the time the operating system is running. No switch_root/pivot_root takes place. Is this kind of setup easy to pull off with ...
2
votes
1answer
1k views

Proper manual OS setup on LUKS encrypted drive with non-aes algorithm on yum-based distro (CentOS)

I'm trying to achieve LUKS-encrypted CentOS 7 install with separate /boot partition and lvm on EFI-friendly motherboard. I've done partitioning fresh CentOS install from old CentOS(installed from GUI)...
7
votes
2answers
781 views

Repack the filesystem image from vmlinux.bin (embedded initramfs) without rebuilding?

In How do I extract the filesystem image from vmlinux.bin? and https://wiki.gentoo.org/wiki/Custom_Initramfs#Salvaging methods are presented for getting and unpacking an embedded initramfs/initrd ...
0
votes
1answer
910 views

uCLinux (linux 4.9 nommu) VFS: Cannot open root device “(null)”

I'm stuck with this kernel panic. What I want is to embed an initramfs into the kernel xip Image, but linux panic and tell me to pass a valid "root=" rootfs value. But WHY does Linux look for this ...
2
votes
2answers
868 views

Why don't we include File System drivers in the kernel itself instead of using Initrd/Initramfs

The Linux kernel contains very minimal code that is necessary to boot on a majority of devices but I don't get the point of having Initrd/Initramfs.As far as I've understood Initrd/Initramfs job is to ...
2
votes
1answer
1k views

switch_root gives Invalid argument

My goal is to unmount the root disk so I can format it. To do this, I want to switch root from the hard disk to some other root. I have chosen to use the files from the initramfs (which contains a ...
2
votes
2answers
533 views

Initramfs and Block Devices

In this introduction to initramfs, Robert Landley mentions the following as the motivation behind ramfs. But ramdisks actually waste even more memory due to caching. Linux is designed to cache ...
1
vote
1answer
282 views

How to use only automatically build RAID arrays on Ubuntu?

I have an Ubuntu 16.06 system where / on an SSD primary partition and /home with md RAID0 on four SSD devices. The file /etc/mdadm/mdadm.conf is automatically generated by mkconf and contains no ...
2
votes
1answer
3k views

Patching the kernel to allow booting without initrd

The first answer of 'Why does Linux use an Initial Ram Disk at boot?' states that the initrd/initial ram filesystem is used to provide drivers to mount the real root filesystem. It also says that it ...
3
votes
3answers
3k views

Why do we need initramfs and initrd

For example we have exotic file system on the disk and in order to load system we need mount root filesystem. But we cannot because there is no suitable driver exists in kernel image. Let me ...
15
votes
1answer
20k views

What is the equivalent of mkinitcpio.conf on debian?

I want to review that the hooks used to build the initrd.img are correct in my debian but I fail to find the /etc/mkinitcpio.conf file like the one in Archlinux, what is the equivalent of this file in ...
2
votes
0answers
600 views

Cannot boot kali linux after dist-upgrade, stucks at 'Loading initial ramdisk …'

I did a dist-upgrade from 4.3.0-kali1-amd64 to 4.4.0-kali1-amd64 but when I restart, the screen stucks at 'Loading initial ramdisk ...'. I had to use the advanced boot options to boot using 4.3.0-...
14
votes
3answers
6k views

Is the entire kernel loaded into memory on boot?

I read through this popular IBM doc (I see it referred quite often on the web) explaining the function of the initial RAM disk. I hit a wall in conceptualizing how this works though. In the doc it ...
2
votes
2answers
815 views

Is there a way to get Linux to treat an initramfs as the final root filesystem?

I want to boot a system with an initramfs that's the actual final filesystem, not a temporary initramfs for loading drivers. Unfortunately, Linux imposes different (and in my case, undesirable) ...
1
vote
0answers
360 views

Mounting real rootfs after initial booting using initrd

I'm booting kernel with root=/dev/ram0 on a embedded environment. After initial booting, how can I mount real rootfs present at /dev/mtd3 and make it as the only rootfs. I'm using root=/dev/ram0 ...
0
votes
1answer
867 views

how to add application to initrd.gz

I have an initrd.gz (from linux parag*n live cd) I want to edit the file inside and add app like apache,ophcrack,etc. So far I've done extracting by following these step wiki.ubuntu.com/...
2
votes
1answer
1k views

How can I replace root / filesystem with another filesystem?

When the Linux kernel starts up, it uses initrd as the root / filesystem, then replaces that with a filesystem partition in fstab. Based on a test in an early init script, I want to replace that root ...
-3
votes
1answer
263 views

Which would mount faster initrd or initramfs ? [closed]

I want to boot my linux as fast as possible. I have to make a choice between initrd and intiramfs. Which one should mount faster and have smaller size?
2
votes
0answers
1k views

Why do I need to specify two init images - initrd and boot - inside KVM to boot to bash?

My machine is running inside a KVM virtual machine (Parallels Desktop v8), having a BIOS (not UEFI), having one SATA drive connected, one GPT partition on that disk, the partition is ext4 formatted, ...
1
vote
1answer
391 views

Using qemu to boot OpenSUSE (or any other OS) with custom kernel

I want to run OpenSUSE as guest with a custom kernel image which is on my host machine. I'm trying: $ qemu-system-x86_64 -hda opensuse.img -m 512 -kernel \ ~/kernel/linux-git/arch/x86_64/boot/...
3
votes
1answer
486 views

initrd or ramfs for SLES as /

I would like to boot a SLES and run it out of a ramdisk. I would like to setup machines so that they start PXE boot and as part of the PXE boot process they pull across an image that is the root ...
10
votes
1answer
6k views

How can I force a Ubuntu kernel to fail mounting / and drop into the initramfs rescue shell?

I am trying to customize the initramfs rescue environment and would like to force the kernel to fail mounting / and drop into the (initramfs) rescue shell, as opposed to single user mode. How can I ...
5
votes
3answers
4k views

Does /init (or /linuxrc) script creates temporary device nodes in /dev?

Considering that GRUB executes following lines: kernel /vmlinuz root=/dev/sda1 ro initrd /initrd On boot, how does the Linux kernel finds out about /dev/sda1 device node? I know that initrd/...
3
votes
1answer
839 views

When would an initrd be necessary?

I've read that I can boot the kernel without initrd, and I've also read that additional modules are loaded during the initrd stage -- as I understand it, for necessary drivers that weren't included in ...