How to fix run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1 in APT

First, verify if /boot has enough free space. The initramfs images can be quite large.

df -h /boot

If /boot is nearly full (90%+ used), you need to free up space before retrying the kernel update. Typical requirement is at least 50-100MB free space.

If /boot is full, remove old kernel versions that are no longer needed:

sudo apt autoremove --purge

This command removes old kernel packages automatically. You can also manually purge specific old kernels:

sudo apt purge linux-image-X.X.X-XX-generic linux-headers-X.X.X-XX-generic

Replace X.X.X-XX with the actual kernel version number. Always keep at least one working kernel version.

Attempt to configure any broken packages and fix broken dependencies:

sudo dpkg --configure -a
sudo apt --fix-broken install

These commands will try to complete any pending package installations or repairs. Run them sequentially.

The initramfs-tools package itself may be corrupted. Reinstall it:

sudo apt install --reinstall initramfs-tools initramfs-tools-core

This will restore the package from the repository and re-run its post-installation scripts.

If the above steps don't work, manually regenerate the initramfs for your current kernel:

sudo update-initramfs -u -k all

The -u flag updates existing initramfs images, and -k all applies to all kernels. This bypasses the post-installation hook and generates initramfs directly.

If the above steps don't resolve the issue, run the script directly to see the specific error:

sudo /etc/kernel/postinst.d/initramfs-tools $(uname -r) /boot/vmlinuz-$(uname -r)

This will show you the exact failure message. Check for errors related to:
- Missing tools (gzip, cpio, lz4)
- Hook script failures in /usr/share/initramfs-tools/hooks/
- File system permission issues

Review detailed logs:

sudo journalctl -xe
dmesg | tail -50