I have put my Rocky Linux 9 SSD in my new PC that uses UEFI boot to load Windows 11, but I can not see the drive in the UEFI boot menu. How do I add this drive to the boot menu so I can choose to load either Windows 11 or Rocky Linux 9? Thanks. I am sure I already have the UEFI files on the SSD, but I am not sure how to tell my PC about it.
How to dual boot two separate OS’s on separate drives is somewhat Mother Board dependent. Meaning the how varies per the firmware. So here are some things to try. First enter your boards firmware and see if windows fast boot is enabled, if it is, disable that as it stores an image of the windows system in memory and will be the first thing booted. Once that is done reboot to confirm W11 comes up as expected. Next, turn off the pc and disconnect the windows drive while keeping the Rocky drive connected. Reboot and see if the Rocky drive is now detected and the secure boot cert process is initiated. If that doesn’t work at first you may have to enter the firmware directly and find the secure boot settings page where you might find a menu for detecting and confirming certs there directly. Once you can boot into your Rocky DE and all is well, shutdown and reconnect the W11 drive and boot. When the MB Logo appears you want to press the key that gets you to the firmware boot menu, where you should see a choice of booting the W11 disk or Rocky. Since the EFI partitions for each OS is on a different drive you will have to use the firmware menu to select which OS. The BLS spec that Rocky uses to boot does not recognize EFI entries on separate partitions by design. There are ways to get around this but I don’t have the layout to test.