Select disk to boot from

I have a desktop computer with Windows 10 on one SSD and another HDD with files, programs, etc. I also have another empty SSD in which I want to install Ubuntu, and let it connected with the others.

What should should I do to have some kind of startup selection screen where I can choose what OS to boot?

I have seen that Grub can make something similar, but with OS's installed in the same disk. Maybe the BIOS would let me select the disk (if it has an option and I configure it)?

4 Answers

Not all BIOS have a boot selection choice. If yours does, you probably have to call for it at boot time with a function keystroke. This all depends on your motherboard's BIOS design.

If you want to have a start-up selection screen to chose the OS, install Ubuntu on the 2nd SSD and during installation point the installer to put GRUB in the same drive (2nd SSD). I am almost 100% sure that this way, if you remove the 2nd SSD, the Windows bootloader will remain in the 1st SSD, letting you boot into Windows like before. So do not put GRUB on the 1st SSD! Even if you wanted to install GRUB on the 2nd SSD, but selecting which drive (and this way which OS) to boot from BIOS, when you would select the 2nd SSD, you would see the Windows selection there, because when GRUB is installed, it searches for all OSs in a computer and lists them all.

Using vasilis74's idea, I installed the OS's as he said, but Grub2 didn't display the selection menu. Using K7AAY's idea I looked for a boot menu in my motherboard, and found that pressing F12 lets me select the disk with the OS I want.

I know it's an old question but it's the first result on Google for linux select boot disk and I found a workaround... kinda

Ubuntu starts up extremely fast compared to Windows for me, and it also has the capability to change boot disk for next startup, so I plugged the Ubuntu SSD into my default boot SATA port and created the following script:

sudo su - <<EOF
efibootmgr -n 0003
reboot
EOF

You need to know which disk is Your Windows boot disk according to efibootmgr (that's simply the efibootmgr command and then You hopefully recognise the SSD by name in the list), and give passwordless sudo permissions to Your user, but then just place this four line shell script on Your Ubuntu desktop and it reboots Your PC with Windows whenever You need it.