I have three OS installed on my PC: Windows 10 and Ubuntu 18.04 on a HDD, and an Ubuntu 20.04 on a SSD. The bootloader is on the HDD.
After a typical update from 18.04, the GRUB was rewritten, and now I only have access to those OSs that are installed on the HDD.
I would like to rescue that GRUB install from Ubuntu 20.04, so I can restore access to all OSs, so I wonder which is the best procedure to do that. I apologize in advance if this is a solved question, but any hint in that respect would be nice.
I provide my fdisk -l results for more information. Thanks!
Disk /dev/sda: 931,5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: C4EF944E-5B36-4774-9395-BA8922E84757
Device Start End Sectors Size Type
/dev/sda1 2048 534527 532480 260M EFI System
/dev/sda2 534528 567295 32768 16M Microsoft reserved
/dev/sda3 567296 996851711 996284416 475,1G Microsoft basic data
/dev/sda4 1918451712 1920458751 2007040 980M Windows recovery environment
/dev/sda5 1920458752 1953511423 33052672 15,8G Microsoft basic data
/dev/sda6 996851712 1012852735 16001024 7,6G Linux swap
/dev/sda7 1012852736 1918451711 905598976 431,8G Linux filesystem
Disk /dev/nvme0n1: 477 GiB, 512110190592 bytes, 1000215216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
boot-repair
? (It has to be run from a live session) – Nmath Sep 10 '20 at 21:32https://paste.ubuntu.com/p/CKs8SrC9VY/
– Gustavo Espínola Mena Sep 10 '20 at 22:30sda
, but it does also show 20.04 on the nvme. Are all three installed using either UEFI or BIOS/legacy? They should all be the same. And if they are UEFI, you need to keep all OS drives connected during installation (otherwise maybe you have a duplicate EFI on the nvme). You should only have one EFI partition for the whole device – Nmath Sep 10 '20 at 22:57However, I do remember that, when I was installing Ubuntu 20.04 on my SSD, I have chosen to format the entire SSD as ext4 and mount as /, as well as /dev/sda bor boot loader installation.
That seemed to work just fine as I was able to choose between 18.04, 20.04 and W10 on boot, but after this 18.04 update, I can't do that anymore (only 18.04 or W10).
Should I have chosen the /dev/sda1 instead? The EFI System partition that is in the HDD?
– Gustavo Espínola Mena Sep 10 '20 at 23:48sda
. However something seems fishy about the nvme not being able to find a MBR or GPT partition scheme. Are you able to use your file manager to mount this drive and navigate the file system? MBR/BIOS/Compatibility are all associated together and are the "old way" of partitioning/booting volumes. Newer hardware uses GPT/UEFI for the same purpose. The most important thing for dual boot is that you're consistently using one or the other. Sorry at this point I can't think of much else to review. Puzzling.. – Nmath Sep 11 '20 at 00:16