---
title: Troubleshooting issues with faulty kernel installations
description: Learn how to troubleshoot and resolve issues caused by faulty kernel installations with our comprehensive guide.
tags: kernel faulty-kernel reboot bugfix
dates:
validation: 2025-07-15
posted: 2022-11-23
---
import Requirements from '@macros/iam/requirements.mdx'
[Rescue mode](/instances/concepts/#rescue-mode) allows you to boot your Instance into a temporary operating system, running from the Instance's RAM. Rescue mode is often used to diagnose and resolve issues such as faulty kernel configurations, networking issues, firewall configurations, and more.
- A Scaleway account logged into the [console](https://console.scaleway.com)
- An [Instance](/instances/how-to/create-an-instance/)
- Installed and configured the Scaleway [CLI](/instances/api-cli/creating-managing-instances-with-cliv2) on your local computer
1. Switch the Instance's `boot-type` to `rescue` and reboot your Instance into rescue mode using the CLI-Tools:
```bash
scw instance server update {Instance_ID} boot-type=rescue
scw instance server reboot {Instance_ID}
```
Replace `{Instance_ID}` with the unique ID of your Instance, e.g. `0500ebd2-d70d-49af-a969-3ac09b6f7fff`.
2. Once the Instance is rebooted, log into your Instance using [SSH](/instances/how-to/connect-to-instance/) and set up the environment to be able to chroot into it:
```bash
cat /proc/partitions
major minor #blocks name
8 0 9765625 sda
8 1 9634536 sda1
8 14 3072 sda14
8 15 126976 sda15
```
Then mount the partitions:
```
mount /dev/sda1 /mnt
mount /dev/sda15 /mnt/boot/efi
mount -o bind /sys /mnt/sys
mount -o bind /proc /mnt/proc
mount -o bind /dev /mnt/dev
```
3. Once mounted, use the `chroot` command to get into your Instances' root file system. You can then change the `GRUB_DEFAULT` value to boot using the previous kernel:
```bash
chroot /mnt
nano /etc/default/grub
```
In the example above, we use `nano` as text editor. Feel free to use your favorite text editor to edit the file.
Change the value of `GRUB_DEFAULT` to `"1 > 2"`:
```bash
# head /etc/default/grub
# If you change this file, run 'update-grub' afterward to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'
GRUB_DEFAULT="1>2"
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT=""
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200 earlyprintk=ttyS0,115200 consoleblank=0"
```
Save the file and exit the text editor.
4. Update the `grub` boatloader` to apply the kernel's update:
```
# update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.0.0-0.deb11.2-cloud-amd64
Found initrd image: /boot/initrd.img-6.0.0-0.deb11.2-cloud-amd64
Found linux image: /boot/vmlinuz-5.19.0-0.deb11.2-cloud-amd64
Found initrd image: /boot/initrd.img-5.19.0-0.deb11.2-cloud-amd64
Found linux image: /boot/vmlinuz-5.10.0-19-cloud-amd64
Found initrd image: /boot/initrd.img-5.10.0-19-cloud-amd64
done
```
5. Switch back the Instance's `boot_type` to `local` and reboot the Instance:
```bash
scw instance server update {Instance_ID} boot-type=local
scw instance server reboot {Instance_ID}
```
Your Instance reboots on the previously installed kernel.
### Examples of failed boots
* In the following example, the Instance may only boot with the root file system in `read-only` mode:
```bash
[ OK ] Finished Remove Stale Onli…ext4 Metadata Check Snapshots.
[ 4.219158] cloud-init[542]: Traceback (most recent call last):
[ 4.220328] cloud-init[542]: File "/usr/bin/cloud-init", line 33, in
[ 4.221518] cloud-init[542]: sys.exit(load_entry_point('cloud-init==20.4.1', 'console_scripts', 'cloud-init')())
[ 4.223064] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 891, in main
[ 4.224435] cloud-init[542]: retval = util.log_time(
[ 4.225251] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 2348, in log_time
[ 4.226838] cloud-init[542]: ret = func(*args, **kwargs)
[ 4.227743] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 600, in status_wrapper
[ 4.229478] cloud-init[542]: util.ensure_dirs((data_d, link_d,))
[ 4.230501] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1534, in ensure_dirs
[ 4.232014] cloud-init[542]: ensure_dir(d, mode)
[ 4.232540] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1591, in ensure_dir
[ 4.233980] cloud-init[542]: chmod(path, mode)
[ 4.234756] cloud-init[542]: File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1830, in chmod
[ 4.235672] cloud-init[542]: os.chmod(path, real_mode)
[ 4.236227] cloud-init[542]: OSError: [Errno 30] Read-only file system: '/var/lib/cloud/data'
[FAILED] Failed to start Apply the …ngs specified in cloud-config.
```