You are right. The kernel file grows and grows and grows. I never said that it's perfect. You seem to understand well what I'm trying to do and you are able to give good suggestions. It's me that I'm not a pro. I'm a hobbyist. Anyway,you suggested the road to take. It seems that there isn't any CPIO parameter that overwrites the old image. Is this correct ? I remember that the old method (unpack and repack the files inside the kernel image) failed. I'm not able to understand why. Some one of you gave a look at the commands that I have used ? Men,I try to do my best,but as I said,I'm not a pro. I presume that,if there isn't any CPIO parameter that overwrites the old image,the only chance that I have to avoid that the kernel file grows forever is to unpack,delete the unwanted files and repack it. If you agree with that,I wish to use that method. But to do that I need someone of you give me some indication about how it didn't work. Below I have repeated the commands that I have used,since the older ones may get lost in the space :
cd /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot
gunzip initrd.img-5.10.0-19-amd64.gz : has been produced a cpio file called : initrd.img-5.10.0-19-amd64
mv initrd.img-5.10.0-19-amd64 initrd.img-5.10.0-19-amd64_
cpio -idv < initrd.img-5.10.0-19-amd64_ : it has been unpacked and then I've copied the files inside a folder called initrd.img-5.10.0-19-amd64
cd /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64/
cp /usr/share/plymouth/debian-logo.png /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64/usr/share/plymouth/
cp /usr/share/plymouth/themes/homeworld/debian.png /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64/usr/share/plymouth/themes/homeworld
cp /usr/share/plymouth/themes/homeworld/logo.png /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64/usr/share/plymouth/themes/homeworld
mv initrd.img-5.10.0-19-amd64 initrd.img-5.10.0-19-amd64-
cd /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64-
find . -print -depth | cpio -ov > ../initrd.img-5.10.0-19-amd64 : generated the cpio file called initrd.img-5.10.0-19-amd64
cd ..
gzip initrd.img-5.10.0-19-amd64 : generated the gzip file called "initrd.img-5.10.0-19-amd64"
cd /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-root/boot/
mv initrd.img-5.10.0-19-amd64 initrd.img-5.10.0-19-amd64_
cp /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-disk/boot/initrd.img-5.10.0-19-amd64.gz /home/ziomario/Scrivania/PassT-Cubic/Debian-new/custom-root/boot/
size
of the new (initrd.img-5.10.0-19-amd64) file is 178.4 MiB (187,099,720
byte),of the old one is : 78.8 MiB (82,661,551 byte) ; so probably there
is something not good if the sizes are so different ? I tried to boot the new ISO image generated by cubic but I've got the following error : https://ibb.co/GCBFcpK that's it. Or maybe another solution is to append a new image inside the kernel image only when a new kernel is detected. In this case I need to study deeply how to do that. At the moment I have no idea.