Not exactly. When installing Debian Xfce, you let the installer use and format the existing swap. Formatting changes the swap UUID, so the original UUID in Debian KDE's fstab, resume and initramfs did not match the new swap UUID any more.emil_21 wrote:Somehow during the installation the id for swap partition in debian kde install was messed up in /etc/initrmfs-tools/conf.d/resume and in /boot/initrd.img-4.9.0-9-amd64. Correct?
Bottom line : do not let the Debian installer use an existing swap partition used by another system unless you know exactly what you are doing. If you have enough disk space, use a separate swap space for each system. Otherwise, it is easier to add an existing swap after the installation.
Side note : sharing the swap space prevents hibernating a system and rebooting to the other.
Globally correct.emil_21 wrote:Also, if i understand correctly how the multiboot system is working the last installed OS, in my case debian xfce, will install grub in mbr sector. So, if i run 'update-grub' from debian kde this will not update grub in mbr sector, i have to run 'update-grub' from debian xfce to update grub in mbr sector. Correct?
The last installed OS installed GRUB where you told it to. If you did not want to install it in the MBR, you could select another location. Any ext4 partition on the same disk as the root partition is fine.
During the installation of the latest system (Debian Xfce), if you chose to install GRUB in the MBR, then it replaced the existing GRUB (installed by Debian KDE) and took over the boot process.
Any GRUB instance uses the config file grub.cfg generated by its owner system. grub.cfg must be updated (by update-grub) after installing a new kernel. This is done automatically on the system the kernel is installed on, but not on the system which owns the active GRUB if different. So you must do it manually.
Note that there are other ways to manage multiboot which do not require to update the active GRUB.