Dual-Booting Solus Plasma With UEFI

kodm

I had already Solus Budgie and Windows 10 installed and now I installed Solus Plasma selecting manually the partitions.
Problem: the PC starts directly into Solus Plasma now, and I don't have the option to choose between Budgie, Plasma and Windows 10 on startup.
The only way to enter into Windows 10 is when I enter into Bios at startup and select the Windows boo tloader.
No boo tloader anymore available for Solus Budgie.

How can I add the Solus Budgie and Windows 10 to the UEFI boot loader so that I can choose between the 3 OS at startup?

sgvd

Can you hold spacebar while booting and see if you can get into the bootloader? If that works, can you mention here what your options are?
Do you have them all use the same boot/efi partition?

kodm

Holding the spacebar while booting does not do allow me to enter into the bootloader.

Starting Solus Budgie (with dual boot options for Windows 10)
"parted -ls" gives me the following result with only one partition flagged as boot,esp
Number Start End Size File system Name Flags 2 473MB 1078MB 605MB fat32 EFI system partition boot, esp

"fdisk -lu|grep -i efi" gives the following result:
/dev/sda2 923648 2104513 1180866 576,6M EFI System

Starting Solus Plasma (without any dual boot options)
"fdisk -lu|grep -i efi" gives the following result:
/dev/sdb2 923648 2104513 1180866 576.6M EFI System

"sudo lsblk -f" gives the following result:
NAME FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT sda ├─sda4 ntfs DATA 70ACE29AACE25A5C 250.2G 51% /mnt/DATA └─sda5 ntfs X-DATA 01D484822523B8E0 41.9G 90% /mnt/XDATA sdb ├─sdb1 ntfs DC746AEF746ACBB8 ├─sdb2 vfat B776-99C0 ├─sdb3 ├─sdb4 ntfs 1C4C848C4C8461FE 51.6G 62% /mnt/WINOS ├─sdb5 ntfs 58CCB9DECCB9B71A ├─sdb6 ext4 18794366-3e16-43c9-96e4-19a6b6b176db ├─sdb7 ext4 LINDAT 5659b11b-9e25-4c81-a844-2a9854be2882 ├─sdb8 swap d050c8f2-0866-4e58-92e3-08037e995100 └─sdb9 ntfs SYN 5FEC472319D086EC 239.3G 55% /mnt/SYN sdc ├─sdc1 ├─sdc2 ntfs SYN-2 92601A82601A6D6B ├─sdc3 ext4 e51ceffe-b392-4339-81bc-d5b7fa3862a8 41.9G 15% / ├─sdc4 vfat B EFBD-6DAD ├─sdc5 ext4 6c2b247d-e55c-4bb3-a8ea-cc76b5e566e0 265G 0% /home └─sdc6 swap 2f3bda7d-985f-462f-980f-a88c56e0b33d [SWAP]

sgvd

Can you do the following and see if the bootloader shows on startup:
sudo clr-boot-manager set-timeout 5 && sudo clr-boot-manager update

(from: https://getsol.us/articles/troubleshooting/boot-management/en/)

I assume all are installed in UEFI mode, so clr-boot-manager must be the boot manager used by Plasma/Budgie. This should present itself on boot when spacebar is hold down. However, this command should make the boot manager appear also by default.
(The default timeout is 0, this changes it to 5, show it should be visible for 5 seconds)

Edit: Never mind. I see that budgie boot has a different efi partition (/dev/sda2). Probably windows boot is in that one as well. Hence it is expected that Plasma (/dev/sdb2) cannot find windows/Budgie installations, as only the current disk is searched (in short, you will have to use the bios menu to switch between Budgie/Windows and Plasma).

Try to add Budgie to the bios boot menu by doing:
sudo efibootmgr -c -d /dev/sda -p 2 -l "\EFI\systemd\systemd-bootx64.efi" -L "Budgie Boot"