Make Bootable USB for Custom Kernel

Environment

• Host: Dell XPS (2023)

Prerequisites

• A compiled kernel source tree (with bzImage built)
• grub-mkrescue installed (sudo apt install grub-pc-bin grub-efi-amd64-bin xorriso mtools)
• A USB drive

1. Kernel Config Requirements

Ensure these are set in .config before building (required for UEFI framebuffer output on XPS):

CONFIG_EFI=y
CONFIG_EFI_STUB=y
CONFIG_DRM=y
CONFIG_DRM_SIMPLEDRM=y
CONFIG_SYSFB=y
CONFIG_SYSFB_SIMPLEFB=y
CONFIG_FB=y
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY=y

Then resolve dependencies and build:

make olddefconfig
make -j$(nproc)

2. Create ISO Directory Structure

e.g., can be found on https://zenodo.org/records/15022146

mkdir -p iso/boot/grub
cp arch/x86/boot/bzImage iso/boot/bzImage
cp /path/to/initramfs.cpio.gz iso/boot/initramfs.cpio.gz

3. Create grub.cfg

Write iso/boot/grub/grub.cfg:

menuentry 'expos' --class os {
    insmod gzio
    insmod part_gpt
    insmod part_msdos
    linux  /boot/bzImage nokaslr no5lvl
    initrd /boot/initramfs.cpio.gz
}

4. Build ISO

grub-mkrescue -o expos.iso iso/

5. Flash to USB

Before run this you have to figure out which device is your USB.

DON’T FLUSH TO YOUR OTHER DEV!

sudo umount /dev/<sd?>*
sudo dd if=expos.iso of=/dev/<sd?> bs=4M status=progress
sync
sudo eject /dev/<sd?>

6. Boot on XPS

1. F12 at boot -> Disable Secure Boot (Security -> Secure Boot -> Disabled)
2. F12 at boot -> Select the USB drive
3. GRUB menu appears -> Select “expos”