create-bullseye-rt.md

Another attempt to update the kernel as chroot. This attempt worked !

Fresh host system install from usb, to ensure we have a correct starting point, and our host system will be the same as our target os. https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/weekly-live-builds/amd64/iso-hybrid/debian-live-testing-amd64-xfce+nonfree.iso

Add sources :

sudo echo "deb http://ftp.de.debian.org/debian bullseye main contrib non-free" > /etc/apt/sources.list 
sudo echo "deb-src http://ftp.de.debian.org/debian bullseye main contrib non-free" >> /etc/apt/sources.list
sudo echo "deb http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list
sudo echo "deb-src http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list
# For newest kernels :
    echo "deb http://deb.debian.org/debian sid main contrib non-free" >> /etc/apt/sources.list
    echo "deb-src http://deb.debian.org/debian sid main contrib non-free" >> /etc/apt/sources.list

sudo apt-get update 

sudo apt-get install linux-image-5.10.0-5-rt-amd64

Reboot. Started in new kernel, remove old kernel :

sudo apt-get remove linux-image-5.10.0-4-amd64

Reboot. Everything ok.

mount

Saved output to a textfile "original-mount.txt", 20 mountpoints in file, this to check if later umount is correct.

Install programs as Chroot :

sudo apt-get install squashfs-tools xorriso isolinux geany

mkdir /home
cd home
apt-get install git autoconf
git clone https://github.com/LinuxCNC/linuxcnc.git
cd /home/linuxcnc/debian
./configure uspace

cd /home/linuxcnc/
dpkg-checkbuilddeps

echo "deb http://deb.debian.org/debian buster main contrib non-free" > /etc/apt/sources.list
echo "deb-src http://deb.debian.org/debian buster main contrib non-free" >> /etc/apt/sources.list
echo "deb http://security.debian.org/debian-security buster/updates main contrib" >> /etc/apt/sources.list
echo "deb-src http://security.debian.org/debian-security buster/updates main contrib" >> /etc/apt/sources.list

sudo echo "deb http://ftp.de.debian.org/debian bullseye main contrib non-free" >> /etc/apt/sources.list 
sudo echo "deb-src http://ftp.de.debian.org/debian bullseye main contrib non-free" >> /etc/apt/sources.list
sudo echo "deb http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list
sudo echo "deb-src http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list
apt-get update

apt-get install debhelper libudev-dev tcl8.6-dev tk8.6-dev libtk-img bwidget tclx 
apt-get install asciidoc dblatex docbook-xsl dvipng ghostscript graphviz groff imagemagick inkscape python-lxml 
apt-get install source-highlight w3c-linkchecker xsltproc texlive-extra-utils texlive-font-utils texlive-fonts-recommended 
apt-get install texlive-lang-cyrillic texlive-lang-french texlive-lang-german texlive-lang-polish texlive-lang-spanish 
apt-get install texlive-latex-recommended  python-tk libxmu-dev libglu1-mesa-dev libgl1-mesa-dev
apt-get install libgtk2.0-dev gettext intltool libboost-python-dev netcat libmodbus-dev yapps2
apt-get install libreadline-gplv2-dev python2-dev python-gtk2
apt-get install python-gtk2 python-is-python2 python-dev-is-python2 
apt-get install python3-tk wget

cd /home/linuxcnc/src
./autogen.sh
./configure --with-python=python3
make -j2

#### If it compiles oke. We know dependencies for linuxcnc are ok.


#### Install linuxcnc.deb package to /opt/
cd /home/software
wget https://github.com/grotius-cnc/debian_distro_live_build_post_tweaking/releases/download/1.0.1/linuxcnc.deb
dpkg -i linuxcnc.deb


#### Install ethercat-master

# For newer kernels activate the sid repository, otherwise :
apt-get install linux-headers-$(uname -r)

cd /home/software
wget https://github.com/grotius-cnc/debian_distro_live_build_post_tweaking/releases/download/1.0.0/ethercat-master.deb
dpkg -i ethercat-master.deb

# To be sure
chmod 777 /etc/sysconfig/ethercat
chmod 777 /etc/init.d/ethercat

# Set the crontab -e parameters to boot ethercat at pc's boot time
sudo crontab -e

@reboot echo MASTER0_DEVICE="$(cat /sys/class/net/enp0s25/address)" > /etc/sysconfig/ethercat 
@reboot echo "DEVICE_MODULES=generic" >> /etc/sysconfig/ethercat 
@reboot /etc/init.d/ethercat start

# Install linuxcnc-ethercat
cd /home/software
wget https://github.com/grotius-cnc/debian_distro_live_build_post_tweaking/releases/download/1.0.3/linuxcnc-ethercat.deb
dpkg -i linuxcnc-ethercat.deb

# Qtvcp libs.
apt-get install qttools5-dev-tools qttools5.dev

# Calculator
apt-get install qalculate

# Install qt
cd /home/software
wget https://github.com/grotius-cnc/debian_distro_live_build_post_tweaking/releases/download/1.0.2/qt-creator.deb
dpkg -i qt-creator.deb

# Delete temp sources
rm -rf /home/software

# Exit chroot environent.
umount /dev /dev/pts /sys /proc  # umount /dev gives the message "busy.." 
exit
# Reboot host pc

Unsquash original dvd /live/filesystem.squashfs

Copy the iso file from your usb to your system dir, including the hidden file ./disk

1. Make a /original directory, copy the usb files to here.
2. Make a /remastered directory. copy the usb files to here.

In the /remasterd/live dir do "as root" :

sudo unsquashfs filesystem.squashfs

This will produce the directory : /remasterd/live/squashfs-root/ Remove the original filesystem.squashfs file in /remastered/live/ :

rm -rf filesystem.squashfs

Chroot

In /remastered/live/ do as root :

mount --bind /dev squashfs-root/dev
mount --bind /dev/pts squashfs-root/dev/pts
mount --bind /sys squashfs-root/sys
mount --bind /proc squashfs-root/proc
chroot squashfs-root
export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
export LC_ALL=C
dhclient
echo "deb http://ftp.de.debian.org/debian bullseye main contrib non-free" > /etc/apt/sources.list 
echo "deb-src http://ftp.de.debian.org/debian bullseye main contrib non-free" >> /etc/apt/sources.list
echo "deb http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list
echo "deb-src http://security.debian.org/debian-security/ bullseye-security main" >> /etc/apt/sources.list

# For newest kernels :
echo "deb http://deb.debian.org/debian sid main contrib non-free" >> /etc/apt/sources.list
echo "deb-src http://deb.debian.org/debian sid main contrib non-free" >> /etc/apt/sources.list

apt-get update
apt-get install linux-image-5.10.0-5-rt-amd64 # Install new kernel.
apt autoremove
apt-get remove linux-image-5.10.0-4-amd64 # Remove old kernel.
apt-get install squashfs-tools xorriso isolinux geany # Add some extra programs to test.

umount /dev /dev/pts /sys /proc  # umount /dev gives the message "busy.." 
exit
mount

Save the mount output to "remastered-mount.txt". Compare previous saved "original-mount.txt" with "remastered-mount.txt".

In my case the "remastered-mount.txt" file has 2 mount positions to much. I did a reboot and check. I solved it by :

sudo umount /sys/kernel/debug/tracing

Copy the new initrd, vmlinuz, config, system.map to a higher directory in the hierarchy.

cp /live/squashfs-root/boot/* /live

or :

sudo cp /live/squashfs-root/boot/config-5.10.0-4-rt-amd64 /live/config-5.10.0-4-rt-amd64 
sudo cp /live/squashfs-root/boot/initrd.img-5.10.0-4-rt-amd64 /live/initrd.img-5.10.0-4-rt-amd64
sudo cp /live/squashfs-root/boot/System.map-5.10.0-4-rt-amd64 /live/System.map-5.10.0-4-rt-amd64
sudo cp /live/squashfs-root/boot/live/vmlinuz-5.10.0-4-rt-amd64 /live/vmlinuz-5.10.0-4-rt-amd64

Repack the squashfs-root dir.

mksquashfs squashfs-root/ filesystem.squashfs -comp xz

note : the filesystem.squashfs is limited to 4gb. The pack ratio = 2.95
If your squashfs-root directory = 13 Gb, the packet filesystem.squashfs will be : 4.4 Gb = 13/4.4=2.95.
So for 4gb your squashfs-root dir may be max 11.8 Gb.

Remove or move the modified squashfs-root directory out of the new iso hierarchy.

rm -rf /remastered/live/squashfs-root

Replace the grub.cfg file

cp /boot/grub/grub.cfg /remastered/boot/grub/

Edit the info file in /remastered/.disk/info

Debian 11 Bullseye Rtos

Create new iso /remastered/

xorriso -as mkisofs -V 'Debian 11 Bullseye Rtos' \
-o Debian-11-Bullseye-Rtos.iso -J -J -joliet-long -cache-inodes \
-isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin \
-b isolinux/isolinux.bin \
-c isolinux/boot.cat -boot-load-size 4 -boot-info-table -no-emul-boot -eltorito-alt-boot \
-e boot/grub/efi.img -no-emul-boot -isohybrid-gpt-basdat -isohybrid-apm-hfsplus .

Put the new iso file on your usb device in /remastered/

sudo dd bs=4M if=Debian-11-Bullseye-Rtos.iso of=/dev/sdb conv=fdatasync status=progress

Install new iso file onto a pc, terminal output :

user@debian:~$ uname -a
Linux debian 5.10.0-4-rt-amd64 #1 SMP PREEMPT_RT Debian 5.10.19-1 (2021-03-02) x86_64 GNU/Linux
user@debian:~$ 

So it worked ! Also geany is present in the system menu. I am happy !!!