Hi! As the title says trying to dual boot Mint and Solus; unfortunately when I set on the pc it boots directly into Solus.
I installed Mint several months ago (sda). When Solus 4.5 was released, I installed the KDE offering on its own SSD (sdb). My PC specs: Ryzen 7 5700x + 32Gb ram + Radeon Rx6650XT gpu. In Solus terminal, I tried to mount the Mint sda partitions. Here is what the terminal reported:
snowdust@karibou ~ $ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda      8:0    0 232.9G  0 disk  
├─sda1   8:1    0   512M  0 part  
├─sda2   8:2    0  32.1G  0 part  
├─sda3   8:3    0  24.3G  0 part  
└─sda4   8:4    0  12.6G  0 part  
sdb      8:16   0 232.9G  0 disk  
├─sdb1   8:17   0   512M  0 part  
├─sdb2   8:18   0  32.1G  0 part /
├─sdb3   8:19   0  24.3G  0 part /home
└─sdb4   8:20   0  16.5G  0 part [SWAP]
zram0  252:0    0     8G  0 disk [SWAP]
snowdust@karibou ~ $ sudo mount /dev/sda1 /mnt
[sudo] password for snowdust:
snowdust@karibou ~ $ sudo mount /dev/sda2 /mnt
snowdust@karibou ~ $ sudo mount /dev/sda3 /mnt
snowdust@karibou ~ $ sudo grub-mkconfig -o /boot/grub/grub.cfg
[sudo] password for snowdust:
**/usr/sbin/grub-mkconfig: line 256: /boot/grub/grub.cfg.new: No such file or directory**

sda1 = EFI partition
sda2 = root partition
sda3 = /home partition
sda4 is the swap partition

What am I doing wrong? Would appreciate any feedback to help solve this issue. Thanks in advance to all of you savvy members.

    snowdust This situation is similar to mine, I believe.
    Try increasing your boot time, using this incantation:
    sudo clr-boot-manager set-timeout 10 && sudo clr-boot-manager update
    It will give you 10 seconds to examine your boot options, and should give access to grub as well.

        elfprince First, thanks for replying. I did as you suggested. Upon reboot I got a black screen with the following text:
        Solus 4.5 Resilience
        EFI Default Loader
        Reboot Into Firmware Interface

            snowdust Try booting to the 3rd option, is that BIOS ? What boot choices do yo get there?

                elfprince Booting to the 3rd option gets me to the Asus mobo BIOS. Selecting Boot Menu(F8) gets me to the screen where I select the drive I want to boot to; in my case either Mint or Solus.
                PS: my partition table is GPT and sdb1 partition is EFI w/flags boot,esp.
                Again your assistance is very much appreciated.

                    snowdust where I select the drive I want to boot to; in my case either Mint or Solus

                    Are you able to choose Mint from there?

                        elfprince As I wrote, once in the BIOS, pressing F8 gets me to the BIOS screen where I can choose Mint or Solus.

                            snowdust So, are you able to choose Mint or Solus? I thought that you were not able to boot Mint by regular boot method.

                                elfprince Upon reboot I get a black screen with the following text:
                                Solus 4.5 Resilience
                                EFI Default Loader
                                Reboot Into Firmware Interface

                                When clicking "Reboot Into Firmware Interface", I get to my ASUS motherboard BIOS screen, see image below:
                                ![
                                ]
                                On the bottom right corner of the screen, selecting "Boot Menu(F8)" circled in red by me, I get to the BIOS boot menu screen where I can select the drive I want to boot into. That is to say either drive w/Mint or drive w/Solus.
                                And NO, I cannot boot Mint by any other method.

                                    snowdust Thank you for explaining. That still does not answer my question. We might be misunderstanding each other here. 😂
                                    Ok, Can you actually boot into Mint, or Solus, when you access the boot menu that you circled?

                                    EDIT: From your last line. I guess, this is the only way you can access Mint, from the BIOS (F8) boot menu. That's not so bad then. I thought you were not able to boot Mint at all.

                                    In my case too, Solus 'hijacked' the sda disk for its EFI. However, in my case Solus boot manager includes access to my other ssd drive containing Linux Lite.

                                    Hope you find your answers! 😄

                                      I'm not real clear on what's happening here, though I suspect a UEFI/grub conflict. If you power on, do you go straight into Solus without intervention?
                                      Does spamming f8 while booting take you to the UEFI OS select screen? And from there, can you successfully boot into mint?
                                      If you go into bios advanced mode, there will be a boot menu. You should be able to change boot order there. If you put mint first, it should give you a grub OS select screen.

                                      It looks like you are booting to a USB. An OS is not really designed to boot to USB and is not a good solution. 🙂