View source for User:Pnoecker/Undead USB Install/undead2live

{{warning|this is an experimental page without resolving conclusion.  this is just exploration and experimentation with the goal of making live media.  the grubiso drop in replacement for isolinux within this document is functional, and tested working.}}


*on your host funtoo system emerge tools for cd mastering:

{{console|body=
###i## emerge cdrtools squashfs-tools isomaster libisoburn
}}

make an undead usb from a stage 3 containing networkmanager, xfce4, x11-xorg, fchroot, slim, mtools, and set to auto login as root terminals.  setup slim to boot root so the entire undead key does not have a password.  tidy up the undead key delete the stage3 tarball, delete the sources directory.  insert auto as root's file system in /etc/fstab so it will load in both ext2 & squashfs modes.  partuuid survives the dd procedure so label by that.  patch and rebuild your initramfs to support loading squashfs and rebuild your initramfs.  change the sources version number to reflect your installation.

{{console|body=
###i## emerge livecd-tools && rc-update add autoconfig default
###i## sed '/MODULES_FS/ s/\"$/ autofs4 loop hfsplus isofs overlay squashfs\"/' -i /usr/share/genkernel/arch/$(arch)/modules_load
###i## genkernel initramfs --clean --disklabel --ramdisk-modules --fullname=debian-sources-x86_64-5.10.28_p1
}}

*setup grub to pass the boot=live kernel parameter:
{{file|name=/etc/default/grub|desc=bootlive|body=
GRUB_CMDLINE_LINUX="boot=live live-media-path=/live quiet"
}}

squashfs is read only and requires a tmpfs or overlay filesystem to run properly.  the overlay fstab statement is usually implemented from the overlay upper file system.

{{console|body=
###i## echo "overlay / overlay rw 0 0" > /etc/fstab
###i## echo "tmpfs /tmp tmpfs nosuid,nodev 0 0" >> /etc/fstab
or
###i## echo 'tmpfs / tmpfs defaults 0 0' > /etc/fstab
}}

mount your undead usb key, but not dev sys or any of the other stuff because were going to package it with squashfs.

{{console|body=
###i## mount /dev/funtoo2 /mnt/funtoo
###i## mount /dev/funtoo1 /mnt/funtoo/boot
}}

edit /mnt/funtoo/etc/fstab

{{console|body=
###i## mksquashfs /mnt/funtoo /mnt/filesystem.squashfs
}}

* unmount before pushing squash image to be the new root:

{{console|body=
###i## umount -lr funtoo
}}

maybe we can get our grub loading the squashed image with a command like this.
{{console|body=
###i## dd if=/mnt/filesystem.squashfs of=/dev/funtoo2
}}

instead make a directory named live and have filesystem.squashfs in the directory.
{{console|body=
###i## mkdir /mnt/funtoo/live
###i## cp /mnt/filesystem.squashfs /mnt/funtoo/live
###i## cp /mnt/funtoo/boot/kernel-debian-sources-x86_64-5.10.28_p1 /mnt/funtoo/live/vmlinuz
###i## cp /mnt/funtoo/boot/initramfs-debian-sources-x86_64-5.10.28_p1 /mnt/funtoo/live/initramfs
###i## cp /mnt/funtoo/boot/amd-uc.img /mnt/funtoo/live
###i## cp /mnt/funtoo/boot/early_ucode.cpio /mnt/funtoo/live
}}

{{console|body=
###i## mount /dev/funtoo2 /mnt/funtoo
###i## mount /dev/funtoo1 /mnt/funtoo/boot
}}

chroot into the squashfs image to manipulate grub on the read write fat partition.

{{console|body=
###i## cd /mnt/funtoo
mount -t proc none /mnt/funtoo/proc
mount --rbind /sys /mnt/funtoo/sys
mount --rbind /dev /mnt/funtoo/dev
env -i HOME=/root TERM=$TERM $(which chroot) /mnt/funtoo bash -l
}}

update boot entries so grub boots squashfs:
{{console|body=
###i## cd /boot
###i## ego boot update
###i## grub-mkconfig -o /boot/grub/grub.cfg
}}

*generate mbr/bios eltorito boot image:

*make grubiso, the isolinux drop in replacement:
{{console|body=
###i## grub-mkimage -p /boot -o tmp_core.img -O i386-pc biosdisk iso9660 multiboot normal ls cat help
###i## cat /usr/lib/grub/i386-pc/cdboot.img tmp_core.img > /boot/grubiso.img
}}

*generate uefi eltorito alternate boot image:

{{console|body=
###i## dd if=/dev/zero of=EFI/BOOT/efiboot.img bs=512 count=2880
###i## mkfs.msdos -F 12 -n 'FUNTOO' EFI/BOOT/efiboot.img
###i## mmd -i EFI/BOOT/efiboot.img ::EFI
###i## mmd -i EFI/BOOT/efiboot.img ::EFI/BOOT
###i## mcopy -i EFI/BOOT/efiboot.img EFI/BOOT/bootx64.efi ::EFI/BOOT/bootx64.efi
###i## mv EFI/BOOT/efiboot.img uefi.img
}}

*exit chroot, remount without the /dev & sys so on directories so we can write the iso output:
{{console|body=
###i## exit
###i## umount -lr funtoo
###i## mount /dev/funtoo2 /mnt/funtoo
###i## mount /dev/funtoo1 /mnt/funtoo/boot
###i## cd /mnt/funtoo
}}

generate iso image, and make it hybrid mode so it can be read from both cd/dvd, and usb key.
{{console|body=
###i## xorrisofs -D -r -V "FUNTOO" -cache-inodes -J -l -b boot/grubiso.img -c boot/boot.cat -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/uefi.img -no-emul-boot -o ../custom.iso .
###i## isohybrid --uefi ../custom.iso
}}

or use grubs framework to generate the ISO image.

{{console|body=
###i## grub-mkrescue -J -R -V "${ISO_VOLUME}" -quiet -o ../output.iso .
}}

== Testing ==
Test your iso booting in both bios and uefi mode in virtualbox, or qemu or vmware virtualization.  Once you're satisfied that it works well under virtualization, burn it to a usb key using etcher and test booting on real hardware.

== sources used ==
https://help.ubuntu.com/community/LiveCDCustomization#Assembling_the_file_system
[https://wiki.osdev.org/UEFI#Creating_disk_images alternate boot image osdev guide]
https://github.com/syzdek/efibootiso