Hello guys, As I promised, here a more detailed solution, with the steps I really used:
The problem: * You have a Windows 10 UEFI and a Linux Legacy boot. They both work, but to choose what to boot you need to change the BIOS option each time. Possible solutions discussed in the thread: 1. Let it be. Don't try to fix what ain't broke. 2. Try to make grub legacy find and boot windows 3. Move Linux boot to UEFI as well. Solution I chose was 3: lets move Linux Legacy to Linux UEFI under these conditions. Step-by-step solution to "MY" case. Be careful as your system might have small differences that would make a huge difference in the end. Special attention to /dev/sdXN partition names and the respective UUID used in FSTAB. First step: with a UEFI setup on BIOS, bring up the Linux Legacy. To do this, you need to boot from a USB stick, as your Linux won't boot. Then you need to give control to the Linux on the harddrive (chroot). The steps are: # boot do debian live of your choice, preferred the same version you have on HD. You will need the internet. Check if apt-get is working on your live system. Maybe install some innocuous/small package like "ascii" Create a point for the new root (in my example it is in sda8): # mkdir /mnt/root # mount -t ext4 /dev/sda8 /mnt/root Now we need to setup the EFI boot # mkdir /mnt/rooot/boot/efi Find your current UEFI partition (maybe fdisk -l will help you), then mount it: # mount /dev/sda1 /mnt/rooot/boot/efi Now prep to change root. Mount all essencial filesystems: # mount --bind /sys /mnt/rooot/sys/ # mount --bind /proc /mnt/rooot/proc/ # mount --bind /dev /mnt/rooot/dev/ # mount --bind /dev/pts /mnt/rooot/dev/pts/ # mount --bind /run /mnt/rooot/run/ Be sure the internet will work after chroot with: # cp /etc/resolv.conf /mnt/root/etc/resolv.conf Find the correct UUID of the UEFI partition. You will need this information to add to fstab file. (Use commands like blkid or fdisk -l -o +UUID or ls /dev/disk/by-uuid) Add it to your FSTAB echo "UUID=A2YOUR14-9UUID22 /boot/efi vfat defaults 0 2" >> /mnt/rooot/etc/fstab Now finally, do the magic: chroot /mnt/root You should now "be" on the main Linux on your HD. Test apt-get to be sure with some small/useless package. You really don't want to mess up the following commands! # apt-get install figlet This is the "almost" irreversible part. Until now you were playing with kid's commands. Remove the old legacy grub. Add the new UEFI grub Re-install the grub menu and hopefully it will recognize your windows. # apt-get remove grub-pc # apt-get install grub-efi # grub-install /dev/sda Check if this file exists, to be sure you are on a UEFI partition now: # file /boot/efi/EFI/debian/grubx64.efi Chek also the output of this command and find DEBIAN there: # efibootmgr Go back to your old root # exit Remove your USB-stick and... # reboot Check this website for some other insights: https://blog.getreu.net/projects/legacy-to-uefi-boot/ On my machine I needed also to remove this options in the BIOS: BIOS - removed secure boot That is all. Have a good hacking. My best, Dr. Béco PS. These instructions come WITHOUT ANY WARRANTY. Always have your backup ready to reinstall everything. On Thu, 10 Oct 2019 at 18:15, Beco <r...@beco.cc> wrote: > > Hello all, > > Thank you very much for all this thread and discussion. > > Let me get back to you. > > On Sun, 6 Oct 2019 at 18:26, Pascal Hambourg <pas...@plouf.fr.eu.org> > wrote: > > > Dear Pascal, > > > >> >> If Windows boots in EFI mode : >> Mount the EFI partition on /boot/efi. >> Install grub-efi-amd64. >> Boot some Linux media in EFI mode. >> Chroot into the Debian system, mount the usual pseudo-filesystems >> (/proc, /dev...) and the EFI partition. >> Run grub-install. >> Run update-grub. >> Done. >> >> >> > > Your simplified solution nailed it! Thank you. > > I mark this thread as solved basically because of this small paragraph. So > if you are reading this in the near future trying to find a solution, this > step-by-step and some duckduckgo will get you into business. > > > There are more details for a complete response, and some commands needs to > be in a different order, that I'll reply later in this thread, just to make > sure the procedure that I made and worked flawlessly, is registered for > posterity. > > For now, if you are in a hurry, this answer above will get you in the > right path. > > My best, > > Beco > > > > -- > Dr Beco > A.I. researcher > > "I know you think you understand what you thought I said but I'm not sure > you realize that what you heard is not what I meant" -- Alan Greenspan > > GPG Key: > https://pgp.mit.edu/pks/lookup?op=vindex&search=0x5A107A425102382A > Creation date: pgp.mit.edu ID as of 2014-11-09 > -- Dr Beco A.I. researcher "I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant" -- Alan Greenspan GPG Key: https://pgp.mit.edu/pks/lookup?op=vindex&search=0x5A107A425102382A Creation date: pgp.mit.edu ID as of 2014-11-09
