Fallback initramfs - how to enable it again?

[steve1]

Hi there,

I’d like to use fallback initramfs again and would need a little help. The directory /etc/mkinitcpio.conf.d/ is empty and I could not find a good template, neither do I know the name(s) of necessary file(s) here. Kernels in use are versions 6.12 and 6.18.

Any hints please?

[Nachlese]

The directory you want to look at is:
/etc/mkinitcpio.d/

That is where the .preset files are.

In each one there is a line (the fourth) like this:

PRESETS=('default')

change it to this:

PRESETS=('default' 'fallback')

I never had that line without the fallback option - I removed the keyword myself to disable the generation of the fallback image.

the complete file for the 6.12 kernel currently looks like this, for me:

# mkinitcpio preset file for the '6.12-x86_64' package

#ALL_config="/etc/mkinitcpio.conf"
ALL_kver="/boot/vmlinuz-6.12-x86_64"

PRESETS=('default')

#default_config="/etc/mkinitcpio.conf"
default_image="/boot/initramfs-6.12-x86_64.img"
#default_uki="/efi/EFI/Linux/manjaro-6.12-x86_64.efi"
#default_options="--splash /usr/share/systemd/bootctl/splash-manjaro.bmp"

#fallback_config="/etc/mkinitcpio.conf"
fallback_image="/boot/initramfs-6.12-x86_64-fallback.img"
#fallback_uki="/efi/EFI/Linux/manjaro-6.12-x86_64-fallback.efi"
fallback_options="-S autodetect"

[steve1]

Thank you for this hint, but what would be correct filenames for the .preset files?

This is from my /boot:

$ ll
insgesamt 124952
drwxr-xr-x  7 root root     4096  4. Dez 10:01 .
drwxr-xr-x 17 root root     4096 27. Nov 20:48 ..
-rw-r--r--  1 root root   307200 26. Nov 03:21 amd-ucode.img
drwx------  3 root root     4096  1. Jan 1970  efi
drwxr-xr-x  3 root root     4096 11. Aug 19:27 EFI
drwxr-xr-x  6 root root     4096  4. Dez 10:01 grub
-rw-------  1 root root 39772271  4. Dez 10:01 initramfs-6.12-x86_64.img
-rw-------  1 root root 42378018  4. Dez 10:01 initramfs-6.18-x86_64.img
-rw-r--r--  1 root root 14934016 11. Nov 19:07 intel-ucode.img
-rw-r--r--  1 root root       22  1. Dez 12:43 linux612-x86_64.kver
-rw-r--r--  1 root root       21  2. Dez 05:30 linux618-x86_64.kver
drwx------  2 root root    16384 25. Jul 11:53 lost+found
drwxr-xr-x  2 root root     4096 13. Jul 10:19 memtest86+
-rw-r--r--  1 root root 13914624  2. Dez 14:49 vmlinuz-6.12-x86_64
-rw-r--r--  1 root root 16580800  2. Dez 14:49 vmlinuz-6.18-x86_64

[Nachlese]

@steve1

This is from my /boot:

… not useful

Once you adapt the file(s) in /etc/mkinitcpio.d/...
and regenerate the images
sudo mkinitcpio -P
the fallback file will be in your listing of the contents of /boot

[steve1]

Do I understand you correctly, that inside the directory

/etc/mkinitcpio.d/

the filename is irrelevant? I’m asking since the above directory is empty here.

[Nachlese]

@steve1

Do I understand you correctly, that inside the directory

/etc/mkinitcpio.d/

Yes.

@steve1

the filename is irrelevant?

the name might be irrelevant - I don’t know
the extension (.preset) probably is not irrelevant - I had no reason to try a different one
the content certainly is not irrelevant …

(I only have one kernel, the whole file is posted in my previous comment)

@steve1

I’m asking since the above directory is empty here.

that must be some recent change that I’m not aware of

---

Here is a thread I found by looking for a potential issue:

Mkinitcpio v40 disabled fallback image creation for new installs

maybe it helps

[steve1]

Thank you for your support - it works Obviously the first part of the .preset’s filename does not seem to be important.

Best regards

Stefan

[nikgnomic]

ArchWiki - mkinitcpio - Fallback intramfs generation

As of version 40 of mkinitcpio, fallback initramfs generation is disabled by default.
To enable it:

• Adjust the respective .preset files in /etc/mkinitcpio.d/
  • Disable PRESETS=('default') and enable PRESETS=('default' 'fallback') instead
  • Enable fallback_image="/boot/initramfs-linux-fallback.img"
  • Enable fallback_options="-S autodetect"
• Regenerate initramfs
• Update your boot loader configuration.