Il 05 Mag 2017 19:30, "Nikolaos Milas" <nmilas at noa.gr> ha scritto: On 5/5/2017 3:45 μμ, Gianluca Cecchi wrote: BTW: see also this paragraph in the provided RH EL link: > 24.7.3. Resetting and Reinstalling GRUB 2 > > But i think is not your problem.... > Yes, I have done that, without change in behavior. Also, after changing partitions flag does your fdisk command reflect the > change? > Yes. Is the error during boot the same as the one provided in your first e-mail? > Yes. One final thing. When I had to change boot settings, I made different steps > in choot environment in respect of the indication inside the image you > sent. > > Specifically > > Verify if your boot partition is already mounted under /mnt/sysimage/boot > in your current environment > Yes, it is: sh-4.2# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/live-rw 2.0G 1.1G 930M 54% / devtmpfs 979M 0 979M 0% /dev tmpfs 1001M 4.0K 1001M 1% /dev/shm tmpfs 1001M 8.3M 993M 1% /run tmpfs 1001M 0 1001M 0% /sys/fs/cgroup /dev/sr0 680M 680M 0 100% /run/install/repo tmpfs 1001M 300K 1001M 1% /tmp /dev/mapper/centos-root 18G 1.5G 16G 9% /mnt/sysimage /dev/vdal 497M 192M 306M 39% /mnt/sysimage/boot /tmpfs 1001M 0 1001M 0% /mnt/sysimage/dev/shm If it is mounted on another mount point in your live env go and umount it > and run > mount /dev/vda1 /mnt/sysimage/boot > Didn't need to. then > chroot /mnt/sysimage > OK, I did so: sh-4.2# chroot /mnt/sysimage bash-4.2# when you are in chrooted environment, probably you don't have special files > for vda and vda1 because they are dinamically created; > verify with > > ls -l /dev/vda* > It seems I do have such files: bash-4.2# ls -la /dev/vda* brw-rw----. 1 root disk 252, 0 May 5 16:49 vda brw-rw----. 1 root disk 252, 1 May 5 16:49 vdal brw-rw----. 1 root disk 252, 2 May 5 16:49 vda2 If this is the case, go and create them > > mknod -m 660 /dev/vda b 253 0 > mknod -m 660 /dev/vda1 b 253 1 > Didn't need to. at this point > > grub2-install /dev/vda > and let see the output of the command and its exit code > As usual: bash-4.2# grub2-install /dev/vda Installing for i386-pc platform. grub2-install: error: unknown filesystem. at this point exit chrooted environment (exit) > umount /mnt/sysimage/boot > > reboot and see if anything changes > Didn't do it, because grub2-install above failed, so nothing changed. I am very puzzled with "unknown filesystem". Thanks for your time and help! I am looking forward to reaching a solution! All the best, Nick _______________________________________________ CentOS mailing list CentOS at centos.org https://lists.centos.org/mailman/listinfo/centos Your /mnt/sysimage/boot is under tmpfs not real disk... Try to unmount it and mount the vda1 device instead and then follow the other steps...