Как убедить Debian live, созданную пакетом bootcd из системы, установленной на винчестере, загружаться в RAM полностью?

#!/bin/sh -e
# used for initramfs
export PATH
. /lib/debian-installer/init-debug
debugshell "just booted"

mount /run
mkdir -p /run/lock
mount /proc
mount /sys
/lib/debian-installer/start-udev

init='/bin/busybox init'
for i in $(cat /proc/cmdline); do
	case $i in
		init=/init|init=init)
			# Avoid endless loop
			: ;;
		init=*)
			init=${i#init=} ;;
		noshell)
			sed -i '/^tty[23]/s/^/#/' /etc/inittab ;;
	esac
done
debugshell "before init"
exec $init

set loopback="findiso=${iso_path}"
export loopback
fi

menuentry "Debian GNU/Linux Live (kernel 5.10.0-20-amd64)" {
  linux  /live/vmlinuz-5.10.0-20-amd64 boot=live components splash quiet "${loopback}"
  initrd /live/initrd.img-5.10.0-20-amd64
}

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet toram"
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.

Файловая система Размер Использовано  Дост Использовано% Cмонтировано в
udev               5,6G            0  5,6G            0% /dev
tmpfs              1,2G         8,7M  1,2G            1% /run
/dev/sda1          9,1G         2,2G  6,8G           25% /
tmpfs              5,7G          61M  5,6G            2% /dev/shm
tmpfs              5,0M         4,0K  5,0M            1% /run/lock
tmpfs              1,2G          32K  1,2G            1% /run/user/1000

/etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet toram"
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.

/isolinux/isolinux.cfg

default linux
timeout 50
prompt 1
# KERNEL: /boot/vmlinuz-5.10.0-21-amd64 /boot/initrd.img-5.10.0-21-amd64
label linux
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=auto bootcd=bootcd toram
label hda
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/hda bootcd=bootcd toram
label hdb
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/hdb bootcd=bootcd toram
label hdc
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/hdc bootcd=bootcd toram
label hdd
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/hdd bootcd=bootcd toram
label sr0
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/sr0 bootcd=bootcd toram
label sr1
  kernel /isolinux/vmlinuz
  append initrd=/isolinux/initrd root=/dev/sr1 bootcd=bootcd toram

Файловая система Размер Использовано  Дост Использовано% Cмонтировано в
udev               5,6G            0  5,6G            0% /dev
tmpfs              1,2G         8,8M  1,2G            1% /run
/dev/sdb           981M         981M     0          100% /mnt/bootcd.lower
tmpfs              5,7G          29M  5,6G            1% /mnt/bootcd.upper
overlay            5,7G          29M  5,6G            1% /
tmpfs              5,7G          47M  5,6G            1% /dev/shm
tmpfs              5,0M         4,0K  5,0M            1% /run/lock
tmpfs              1,2G          24K  1,2G            1% /run/user/1000

tmpfs           3.9G     0  3.9G   0% /run
/dev/loop0      2.5G  2.5G     0 100% /ro
overlay         3.9G  1.5G  2.5G  38% /
tmpfs           3.9G     0  3.9G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
tmpfs           3.9G     0  3.9G   0% /tmp
tmpfs           789M   12K  789M   1% /run/user/1000

# vim: set filetype=sh :
#        file: bootcdwrite.conf
#   copyright: Bernd Schumacher <bernd.schumacher@hpe.com> (2001-2020)
#     license: GNU General Public License, version 3
# description: bootcdwrite.conf - default config for bootcdwrite
#
# SRCDISK
#
#   The Variables SRCDISK defines the root of the files
#   that will be copied.
#
#   For example, to build an image from a remote system,
#   export root-directory with nfs,
#   mount it locally to </mnt/remote> and add::
#
#     SRCDISK=/mnt/remote
#
#   It is added as prefix to KERNEL, INITRD, DISABLE_CRON and NOT_TO_CD,
#   if this are relativ paths (without starting "/")
#
#   Default::
#
#     SRCDISK=/
#
SRCDISK="/"
#
# KERNEL
#
#   This defines the kernel which is used.
#   More kernels can be defined with KERNEL<number>
#   The numbers have to start with 1 and can continue with 2, 3, 4 ... ::
#
#     KERNEL1=/boot/vmlinuz-2.6.18-3-686-bigmem
#     KERNEL2=/boot/vmlinuz-4.19.0-5-amd64
#
#   Default::
#
#     KERNEL=vmlinuz
#
KERNEL="/vmlinuz"
#
# APPEND
#
#   This can be used to define additional options for the kernel
#   For more kernels APPEND<number> can be defined::
#
#     APPEND1="vga=normal nomodeset"
#     APPEND2=""
#
#   Default::
#
#     APPEND=""
#
APPEND=""
#
# INITRD
#
#   This defines the path to initrd.
#   For more kernels INITRD<number> can be defined::
#
#     INITRD1=/boot/initrd.img-2.6.18-3-686-bigmem
#     INITRD2="initrd.img"
#
#   Default::
#
#     INITRD="initrd.img"
#
INITRD="/initrd.img"
#
# KLABEL
#
#   This defines a label for the kernel to be choosen when booting from bootcd.
#   Can defines multiple kernels with <KERNEL<number>> and label <KLABEL<number>>::
#
#     KLABEL1=686-3
#     KERNEL1=/boot/vmlinuz-2.6.18-3-686-bigmem
#     INITRD1=/boot/initrd.img-2.6.18-3-686-bigmem
#     APPEND1=
#
#   Default::
#
#     KLABEL=linux
#
KLABEL="linux"
#
# DISPLAY
#
#   Text files to display at boottime (see syslinux doku)
#   When pressing F1 at boot time the file defined by <DISPLAY> is shown.
#   F2 will show the file defined by <DISPLAY2> and F3
#   will show the file defined by <DISPLAY3>
#   F10 lists all people mentioned in <changelog>.
#
#   The text file <kernelinfo> is replaced with a file which includes kernelinfo.
#
#   Default::
#
#     DISPLAY="/usr/share/bootcd/default.txt"
#     DISPLAY2="kernelinfo"
#
DISPLAY="/usr/share/bootcd/default.txt"
#
# TYP
#
#   TYP can be defined as CD or DVD to get a warning if the size of
#   the image will be larger as the specified medium.
#
#   Default::
#
#     TYP=DVD
#
TYP="DVD"
#
# CDDEV
#
#   Specifies one or more CD devices to boot from. The first one is the default.
#   auto tries to find the bootcd on all SCSI and IDE CDROMS
#
#   Default::
#
#     CDDEV="auto /dev/hda /dev/hdb /dev/hdc /dev/hdd /dev/sr0 /dev/sr1"
#
CDDEV="auto /dev/hda /dev/hdb /dev/hdc /dev/hdd /dev/sr0 /dev/sr1"
#
# DO_CHECK
#
#   Enables some checks or not.
#   To check for possible problems can take a long time, but it is recommended to do the checks.
#
#   Default::
#
#     DO_CHECK=yes
#
DO_CHECK="yes"
#
# NOT_TO_CD
#
#   Add directories which should be excluded from bootcd.
#   Directories are separated by spaces.
#   SRCDISK will be automatically added to each path that does not start with "/".
#
#   Default::
#
#     NOT_TO_CD=""
#
NOT_TO_CD=""
#
# SSHHOSTKEY
#
#   If using ssh it is helpful to have a unique ssh hostkey for each CD.
#   To be generated at burntime::
#   Default::
#
#     SSHHOSTKEY=yes
#
SSHHOSTKEY="yes"
#
# UDEV_FIXNET
#
#   If the network interfaces are hardwired in
#   /etc/udev/rules.d/xx_persistent-net.rules
#   they can removed on bootcd, with:
#   Default::
#
#     UDEV_FIXNET="yes"
#
UDEV_FIXNET="yes"
#
# VAR
#
#   This defines the directoy where the image resists after build.
#   Default::
#
#     VAR=/var/spool/bootcd
#
VAR="/var/spool/bootcd"
#
# FLOPPY_RUNTIME_DEV
#
#   When you booting from cd changes will be read from this device.
#   Without a floppy::
#
#     FLOPPY_RUNTIME_DEV=""
#
#   Default::
#
#     FLOPPY_RUNTIME_DEV=/dev/fd0
#
FLOPPY_RUNTIME_DEV="/dev/fd0"
#
# BOOTCDFLOPPY
#
#   If the system should boot the kernel from floppy.
#   This reduces space on floppy used by bootcdflopcp.
#   For this to work FLOPPY_CREATE_DEV has to be specified::
#
#     BOOTFLOPPY=yes|no
#
#   Default::
#
#     BOOTFLOPPY=no
#
BOOTCDFLOPPY=""
#

#
# BOOT_ONLY_WITH_FLOPPY
#
#   If you several machines will be booted from the same bootcd, you must have
#   each one can hav separat configuraiton (exp: /etc/network/interfaces) on floppy.
#   If the floppy can not be mounted, it may be a good idea to stop booting with::
#
#     BOOT_ONLY_WITH_FLOPPY=yes
#
#   Default::
#
#     BOOT_ONLY_WITH_FLOPPY=no
#
BOOT_ONLY_WITH_FLOPPY="no"
#
# CLEAN_VAR
#
#   delete some chached files in /var with:
#   Default::
#
#     CLEAN_VAR=yes
#
CLEAN_VAR="yes"
#
# TO_FSTAB
#
#   To add addiditionel entries to fstab. Use for example::
#
#     TO_FSTAB="/dev/hdc1 /home ext3 defaults 1 1
#
#   Default::
#
#     TO_FSTAB=""
#
TO_FSTAB=""
#
# NOTCOMPRESSED
#
#   Files or Directory-Trees that should never be compressed on CD can be listed here.
#   This can be used for documentation which should be visible without installing the bootcd.
#   Default::
#
#     NOTCOMPRESSED=""
#
NOTCOMPRESSED="/home"
#
# DISABLE_CRON
#
#   Files listed will be on the cdrom with a .no_run_on_bootcd suffix so run-parts won't execute them.
#   The original file will be a link to /bin/true.
#   This is meant for cron maintenance scripts which are useless on a static cdrom.
#   The default is to disable the daily find, standard and security scripts.
#   With bootcd2disk this files will be reactivated again.
#
#   Default::
#
#     DISABLE_CRON="etc/cron.daily/find etc/cron.daily/standard etc/cron.daily/security"
#
DISABLE_CRON="/etc/cron.daily/find /etc/cron.daily/standard /etc/cron.daily/security"
#
# MKISOFS_CHNG
#
#   With this variable some options given to mkisofs by bootcdwrite can be changed.
#
#   Example: To use <-opt1> and <-opt2 <value>> and
#   to not use any previous <-opt1 [<value>...]>, <-opt2 [<value...>]> and
#   <-opt3 [<value>...]> and to leave any other options as defined::
#
#     MKISOFS_CHNG="-opt1 -opt2 <value> !-opt3"
#
#   Default::
#
#     MKISOFS_CHNG=""
#
MKISOFS_CHNG=""
#
# extra_changes()
#
#   It is possible to define a function called extra_changes to have some
#   files modified on the ISO image. Here is an example::
#
#     extra_changes() {
#       bootcd_global VAR
#
#       echo "noname" >$VAR/changes/etc/hostname
#
#       mkdir -p $VAR/changes/etc/network
#       ( echo "auto lo"
#         echo "iface lo inet loopback"
#         echo "" echo "auto eth0"
#         echo "iface eth0 inet static"
#         echo "       address 0.0.0.0"
#         echo "       netmask 255.255.255.0"
#       ) >$VAR/changes/etc/network/interfaces
#
#       echo "127.0.0.1 localhost noname" >$VAR/changes/etc/hosts
#
#       cat $SRCDISK/etc/passwd |
#       grep -v -e "^bs:" -e "^bianca:" -e "^tim:" >$VAR/changes/etc/passwd
#
#       cat $SRCDISK/etc/shadow |
#       grep -v -e "^bs:" -e "^bianca:" -e "^tim:" >$VAR/changes/etc/shadow
#
#       cat $SRCDISK/etc/group |
#       grep -v -e "^bs:" -e "^bianca:" -e "^tim:" >$VAR/changes/etc/group
#     }
#
#   Default::
#
#     # make sure the function is not defined
#     unset -f extra_changes
#
extra_changes() { :; }
#
# BOOTCDMODPROBE
#
#   If booted from initrd bootcd has to load the necessary modules.
#   If only modules provided by initramfs-tools are needed you can
#   specify "standard" here::
#
#     BOOTCDMODPROBE=standard
#
#   If bootcd should try extra hard to load
#   neccessary modules you can specify "bootcd" here.
#   Bootcd will use discover for this purpose. So discover has to be installed::
#
#     BOOTCDMODPROBE=bootcd
#
#   If you specify auto, bootcd will check if discover is installed.
#   If it is installed BOOTCDMODPROBE=bootcd will be set, if not
#   BOOTCDMODPROBE=standard will be set.
#   Be aware that people have reported, that sometimes BOOTCDMODPROBE=bootcd
#   may not work but sometimes it is needed.
#   Default::
#
#     BOOTCDMODPROBE=auto
#
BOOTCDMODPROBE="auto"
#

#!/bin/sh
[ -f /scripts/functions ] && . /scripts/functions

PREREQ=""
prereqs()
{
    echo "$PREREQ"
}

case $1 in
prereqs)
    prereqs
    exit 0
    ;;
esac

# chkerr <EXIT CODE> <action performed>
chkerr()
{
    e=$1
    shift
    if [ $e -ne 0 ]; then
      echo "bootcdoverlayfs: ERROR $e while running: $*"
      echo "try to fix and exit"
      /bin/sh
    fi
}

getiso()
{
  sed -n "s/^.*\<root=iso:\([^ :]*\):\([^ ]*\)\>.*$/\2/p"
}

modprobe aufs || true
modprobe overlay || true

if [ "$(grep "\<bootcd=" /proc/cmdline)" ]; then
    echo "bootcdoverlayfs rootmnt=<$rootmnt>"

    iso="$(cat /proc/cmdline | getiso)"
    if [ "$iso" ]; then
      mkdir /bootcd.disk_with_iso
      mount -o move ${rootmnt} /bootcd.disk_with_iso
      chkerr $? "mount -o move ${rootmnt} /bootcd.disk_with_iso"

      modprobe loop
      mount -o loop -t iso9660 /bootcd.disk_with_iso/${iso} ${rootmnt}
      chkerr $? "mount -o loop -t iso9660 /bootcd.disk_with_iso/${iso} ${rootmnt}"
    fi

    mkdir /bootcd.upper
    mount -t tmpfs tmpfs /bootcd.upper
    chkerr $? "mount -t tmpfs tmpfs /bootcd.upper"

    mkdir /bootcd.lower
    mount -o move ${rootmnt} /bootcd.lower
    chkerr $? "mount -o move ${rootmnt} /bootcd.lower"

    mkdir /overlayfs

    if [ "$(cat /proc/filesystems | grep "\<aufs\>")" ]; then
      mount -t aufs -o dirs=/bootcd.upper:/bootcd.lower=ro aufs /overlayfs
      chkerr $? "mount -t aufs -o dirs=/bootcd.upper:/bootcd.lower=ro aufs /overlayfs"

    elif [ "$(cat /proc/filesystems | grep "\<overlay\>")" ]; then
      mkdir /bootcd.upper/upper
      mkdir /bootcd.upper/work
      mount -t overlay -o lowerdir=/bootcd.lower,upperdir=/bootcd.upper/upper,workdir=/bootcd.upper/work overlay /overlayfs
      chkerr $? "mount -t overlay -o lowerdir=/bootcd.lower,upperdir=/bootcd.upper/upper,workdir=/bootcd.upper/work overlay /overlayfs"

    else
      chkerr 1 "no aufs and no overlay in /proc/filesystems"
    fi

    mkdir -p /overlayfs/mnt/bootcd.lower
    mount -o move /bootcd.lower /overlayfs/mnt/bootcd.lower
    chkerr $? "mount -o move /bootcd /overlayfs/mnt/bootcd.lower"

    if [ "$iso" ]; then
      mkdir -p /overlayfs/mnt/bootcd.disk_with_iso
      mount -o move /bootcd.disk_with_iso /overlayfs/mnt/bootcd.disk_with_iso
      chkerr $? "mount -o move /bootcd.disk_with_iso /overlayfs/mnt/bootcd.disk_with_iso"
    fi

    mkdir -p /overlayfs/mnt/bootcd.upper
    mount -o move /bootcd.upper /overlayfs/mnt/bootcd.upper
    chkerr $? "mount -o move /bootcd.upper /overlayfs/mnt/bootcd.upper"

    mount -o move /overlayfs ${rootmnt}
    chkerr $? "mount -o move /overlayfs ${rootmnt}"
fi

exit 0

#!/bin/sh
# Part of raspi-config https://github.com/RPi-Distro/raspi-config
#
# See LICENSE file for copyright and license details


INTERACTIVE=True
ASK_TO_REBOOT=0

get_overlay_now() {
  grep -q "boot=overlay" /proc/cmdline
}

get_overlay_conf() {
  grep -q "boot=overlay" /boot/grub/grub.cfg
}

get_bootro_now() {
 findmnt /boot | grep -q " ro,"
}

get_bootro_conf() {
  grep /boot /etc/fstab | grep -q "defaults.*,ro"
}

enable_overlayfs() {
  KERN=$(uname -r)
  INITRD=initrd.img-"$KERN"-overlay

  # mount the boot partition as writable if it isn't already
  if get_bootro_now ; then
    if ! mount -o remount,rw /boot 2>/dev/null ; then
      echo "Unable to mount boot partition as writable - cannot enable"
      return 1
    fi
    BOOTRO=yes
  else
    BOOTRO=no
  fi

  cat > /etc/initramfs-tools/scripts/overlay << 'EOF'
# Local filesystem mounting			-*- shell-script -*-

#
# This script overrides local_mount_root() in /scripts/local
# and mounts root as a read-only filesystem with a temporary (rw)
# overlay filesystem.
#

. /scripts/local

local_mount_root()
{
	local_top
	local_device_setup "${ROOT}" "root file system"
	ROOT="${DEV}"

	# Get the root filesystem type if not set
	if [ -z "${ROOTFSTYPE}" ]; then
		FSTYPE=$(get_fstype "${ROOT}")
	else
		FSTYPE=${ROOTFSTYPE}
	fi

	local_premount

	# CHANGES TO THE ORIGINAL FUNCTION BEGIN HERE
	# N.B. this code still lacks error checking

	modprobe ${FSTYPE}
	checkfs ${ROOT} root "${FSTYPE}"

	# Create directories for root and the overlay
	mkdir /lower /upper

	# Mount read-only root to /lower
	if [ "${FSTYPE}" != "unknown" ]; then
		mount -r -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} /lower
	else
		mount -r ${ROOTFLAGS} ${ROOT} /lower
	fi

	modprobe overlay || insmod "/lower/lib/modules/$(uname -r)/kernel/fs/overlayfs/overlay.ko"

	# Mount a tmpfs for the overlay in /upper
	mount -t tmpfs tmpfs /upper
	mkdir /upper/data /upper/work

	# Mount the final overlay-root in $rootmnt
	mount -t overlay \
	    -olowerdir=/lower,upperdir=/upper/data,workdir=/upper/work \
	    overlay ${rootmnt}
}
EOF

  # add the overlay to the list of modules
  if ! grep overlay /etc/initramfs-tools/modules > /dev/null; then
    echo overlay >> /etc/initramfs-tools/modules
  fi

  # build the new initramfs
  update-initramfs -c -k "$KERN"

  # rename it so we know it has overlay added
  mv /boot/initrd.img-"$KERN" /boot/"$INITRD"

  # there is now a modified initramfs ready for use...

  # modify initrd in /boot/grub/grub.conf
  sed -i /boot/grub/grub.cfg -e 's/initrd\.img-'"$KERN"'/'"$INITRD"'/'

  # modify command line
  if ! grep -q "boot=overlay" /boot/grub/grub.cfg ; then
      sed -i '/vmlinuz-'"$KERN"'/ s/$/ boot=overlay/' /boot/grub/grub.cfg
  fi

  if [ "$BOOTRO" = "yes" ] ; then
    if ! mount -o remount,ro /boot 2>/dev/null ; then
        echo "Unable to remount boot partition as read-only"
    fi
  fi
}

is_uname_current() {
  test -d "/lib/modules/$(uname -r)"
  return $?
}

disable_overlayfs() {
  KERN=$(uname -r)
  INITRD=initrd.img-"$KERN"-overlay
  # mount the boot partition as writable if it isn't already
  if get_bootro_now ; then
    if ! mount -o remount,rw /boot 2>/dev/null ; then
      echo "Unable to mount boot partition as writable - cannot disable"
      return 1
    fi
    BOOTRO=yes
  else
    BOOTRO=no
  fi

  # remove the overlay to the list of modules
  if grep -q "overlay" /etc/initramfs-tools/modules ; then
    sed -i /etc/initramfs-tools/modules -e '/overlay/d'
  fi
  if update-initramfs -c -k "${KERN}" ; then
    update-initramfs -d -k "${KERN}-overlay"
  fi

  # modify the initrd in /boot/grub/grub.cfg
  sed -i /boot/grub/grub.cfg -e 's/'"$INITRD"'/initrd\.img-'"$KERN"'/'

  # modify command line
  sed -i '/vmlinuz-'"$KERN"'/ s/ boot=overlay//' /boot/grub/grub.cfg

  if [ "$BOOTRO" = "yes" ] ; then
    if ! mount -o remount,ro /boot 2>/dev/null ; then
        echo "Unable to remount boot partition as read-only"
    fi
  fi
}

enable_bootro() {
  if get_overlay_now ; then
    echo "Overlay in use; cannot update fstab"
    return 1
  fi
  sed -i /etc/fstab -e "s/\(.*\/boot.*\)defaults\(.*\)/\1defaults,ro\2/"
}

disable_bootro() {
  if get_overlay_now ; then
    echo "Overlay in use; cannot update fstab"
    return 1
  fi
  sed -i /etc/fstab -e "s/\(.*\/boot.*\)defaults,ro\(.*\)/\1defaults\2/"
}

do_finish() {
  if [ $ASK_TO_REBOOT -eq 1 ]; then
    whiptail --yesno "Would you like to reboot now?" 20 60 2
    if [ $? -eq 0 ]; then # yes
      sync
      reboot
    fi
  fi
  exit 0
}

do_overlayfs() {
  DEFAULT=--defaultno
  CURRENT=0
  STATUS="disabled"

  if [ "$INTERACTIVE" = True ] && ! is_uname_current; then
    whiptail --msgbox "Could not find modules for the running kernel ($(uname -r))." 20 60 1
    return 1
  fi

  if get_overlay_conf; then
    DEFAULT=
    CURRENT=1
    STATUS="enabled"
  fi
  if [ "$INTERACTIVE" = True ]; then
    whiptail --yesno "Would you like the overlay file system to be enabled?" $DEFAULT 20 60 2
    RET=$?
  else
    RET=$1
  fi
  if [ $RET -eq $CURRENT ]; then
    if [ $RET -eq 0 ]; then
      if enable_overlayfs; then
        STATUS="enabled"
        ASK_TO_REBOOT=1
      else
        STATUS="unchanged"
      fi
    elif [ $RET -eq 1 ]; then
      if disable_overlayfs; then
        STATUS="disabled"
        ASK_TO_REBOOT=1
      else
        STATUS="unchanged"
      fi
    else
      return $RET
    fi
  fi
  if [ "$INTERACTIVE" = True ]; then
    whiptail --msgbox "The overlay file system is $STATUS." 20 60 1
  fi
  if get_overlay_now ; then
    if get_bootro_conf; then
      BPRO="read-only"
    else
      BPRO="writable"
    fi
    whiptail --msgbox "The boot partition is currently $BPRO. This cannot be changed while an overlay file system is enabled." 20 60 1
  else
    DEFAULT=--defaultno
    CURRENT=0
    STATUS="writable"
    if get_bootro_conf; then
      DEFAULT=
      CURRENT=1
      STATUS="read-only"
    fi
    if [ "$INTERACTIVE" = True ]; then
      whiptail --yesno "Would you like the boot partition to be write-protected?" $DEFAULT 20 60 2
      RET=$?
    else
      RET=$1
    fi
    if [ $RET -eq $CURRENT ]; then
      if [ $RET -eq 0 ]; then
        if enable_bootro; then
          STATUS="read-only"
          ASK_TO_REBOOT=1
        else
          STATUS="unchanged"
        fi
      elif [ $RET -eq 1 ]; then
        if disable_bootro; then
          STATUS="writable"
          ASK_TO_REBOOT=1
        else
          STATUS="unchanged"
        fi
      else
        return $RET
      fi
    fi
    if [ "$INTERACTIVE" = True ]; then
      whiptail --msgbox "The boot partition is $STATUS." 20 60 1
    fi
  fi
  do_finish
}

do_overlayfs

# Booting Debian from a RAM disk #
This guide is adapted from http://reboot.pro/topic/14547-linux-load-your-root-partition-to-ram-and-boot-it/

What you need:
* lots of RAM
* Debian based distribution or any that supports booting from initramfs
* mkinitramfs or a tool to build a new initramfs
* some linux knowledge
* no need to create an image
* no need for Grub4Dos
* no need for a "special driver"

Step 1:
Choose a distribution thats supports booting from initramfs. (like ubuntu)

Step 2:
Install to harddisk. Make sure you split it into multiple partitions (/, /boot, /home, swap, ...).

Step 3:
Boot your new system, install updates, drivers if neccessary (this will improve performance), strip it down to the minimum. Every file will be loaded to RAM ! A fresh install uses about 2 GB auf harddisk-space.

Step 4:
modify `/etc/fstab` :

`cp /etc/fstab /etc/fstab.bak` find the line specifing the root partition and change it in:
none / tmpfs defaults 0 0* save

Step 5:
edit the local script in your initramfs:
cd /usr/share/initramfs-tools/scripts/* make a backup of /usr/share/initramfs-tools/scripts/local
cp local local.bak* modify local, find this line:
```
# FIXME This has no error checking

# Mount root

mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} ${rootmnt}
```
change it to:
```
# FIXME This has no error checking

# Mount root

#mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} ${rootmnt}

mkdir /ramboottmp

mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} /ramboottmp

mount -t tmpfs -o size=100% none ${rootmnt}

cd ${rootmnt}

cp -rfa /ramboottmp/* ${rootmnt}

umount /ramboottmp
```
* save
* execute, or rebuild initramfs
mkinitramfs -o /boot/initrd.img-ramboot* replace modified local with original file
cp -f local.bak localStep 6:
* modify this file (needs a better solution)
/boot/grub/grub.cfg* copy the first boot entry and replace the /initrd line with this:
/initrd /boot/initrd.img-ramboot* label the new entry as RAMBOOT
This will boot our generated initramfs instead the original one.
Step 7:
* reboot
* choose standart boot (no ramdisk)
* choose RAMBOOT and all your files on the root partition will be loaded to a tmpfs

For me—running Debian 11 (bullseye)—this line:

/initrd /initrd.img-ramboot

should be:

/initrd /boot/initrd.img-ramboot

Otherwise, it works perfectly on my machine.