Solaris partition in boot screen disappeared - F11??

I have a problem where I installed several OSes as partitions on one disk. And suddenly I cannot see Solaris 11.3 in the bios boot screen anymore. I have no clue why. Do anyone have a suggestion so I can dig further somewhere?

I first installed Solaris 11.3. Then Windows10 (gaming). Then Linux Mint (which is Ubuntu). Now I have three partitions on a single disk.

Then I unplugged this disk, and installed Windows10 again on another disk. The purpose is to create music on this Win10 disk. The reason I unplugged the first disk is because Win10 tends to overwrite other disks when installing. Let me repeat this; if you install Windows10 on a disk, and have a second disk with Solaris/Linux - then Win10 will overwrite the second disk. I dont really know why Win10 overwrites, but it uses the second disk as temporary storage or so. Anyway, your second disk will be overwritten if it is a non NTFS disk. So, when installing Win10, unplug all other non NTFS disks.

After installing was complete, I plugged in both disks. During bios startup, I press F11 and can choose which of these four partitions to boot:
-Windows10
-Ubuntu
-Windows10
-Solaris

Then I unplugged the disks again temporarily while booting up without disks to test and silence the fans. After silencing the fans, I plugged in both disks and voila; Solaris is now gone!!
-Windows10
-Ubuntu
-Windows10

I dont have a clue why?? It worked fine until I unplugged all disks. How can I get Solaris back? I tried to modify Ubuntu using GRUB2 to incorporate the Solaris partition but that does not work. Is it because I must add ZFS drivers to Ubuntu? I would like BIOS to see the Solaris partition again, but dont know how to do that?

You asked a similar but inverted question in 2016.

What's different now?

The difference is that now the Solaris 11.3 partition cannot be seen from the BIOS boot selection screen. I followed the steps in my old thread, i.e. install Solaris first, and then Windows. Still it does not work. I could see Solaris 11.3 partition in the BIOS boot selection screen (pressing F11) until I unplugged the disks. After that, the Solaris partition is gone. There should be something easy to do, to get Solaris back.

I also tried to boot Solaris from the GRUB2 used by Linux, but that does not work. Do I need to install ZFS-on-Linux first? Anyone knows?

Ok, it seems fragile to install Solaris, Win10 and Linux on the same disk. The problem is that if I disconnect the disk, and reconnect it again, then Solaris partition will not be visible in the F11 - boot bios menu. I can only boot Linux and Win10. I do not know how to make bios scan the disk to notice the Solaris partition. I tried a while to get Linux GRUB2 to boot up Solaris partition - but that requires lot of work to make Linux boot ZFS partitions. FreeBSD has ZFS partitions and make Linux boot FreeBSD from GRUB2 reqiures work so GRUB2 can read ZFS partitions.

In the end, I solved this problem by installing Solaris onto a separate disk. When I disconnected Solaris disk and reconnected it again, then bios boot sceen showed the disk. So I could boot solaris by selecting the new disk. Now everything works; I have win10 and Linux on the disk, and Solaris on a separate disk. And if I disconnect and reconnect the solaris disk, then bios will see the entire disk - so I can always boot Solaris.