On Tue, Apr 19, 2016 at 5:42 AM, Jerry Geis <geisj at pagestation.com> wrote: > I have a laptop with windows 10. > I went into the Windows disk manager and shrunk the volume > to make room for C7. That worked. > > I also changed the BIOS from secure boot to "both" (secure/legacy) Both is a problem. There's no practical way for an installer to support both. Basically it makes the computer UEFI for Windows and BIOS for CentOS 7 instead of UEFI for both. > > I installed C7, went fine. About the time it was done I realized I never > saw anything about "other" boot options (seems I saw that in the past). > > Anyway sure enough, got done and C7 boots fine - no option there for > Windows. I did searching and found I needed to add to the > /etc/grub.d/40_custom the following: > menuentry "Windows 10" { > set root='(hd0,1)' > chainloader +1 > } > > then re-run the grub2-mkconfig -o /boot/grub2/grub.cfg > > I then rebooted and sure enough I got the menu item for "Windows 10" > however when I select it it does not boot. > > How do I get Windows 10 to boot again ? You'll have to use the firmware's boot manager. The legacy mode enables a compatibility support module (CSM) so that UEFI presents a faux-BIOS to the operating system, Cent OS in this case. So Cent OS thinks it's on a BIOS system, and installs a BIOS based bootloader. A BIOS bootloader cannot chainload a UEFI bootloader. What you should revert back to UEFI only, with Secure Boot enabled, and reinstall CentOS, deleting the previous partition/mount points including the BIOS Boot partition that was created for CentOS's bootloader. The gotcha is that with Secure Boot enabled, the CentOS GRUB-efi package doesn't support chainloading the Windows bootloader. This is getting fixed in Fedora 24 but I have no idea how long it'll take to get to CentOS 7. You could either disable Secure Boot (which I don't recommend) or you switch between CentOS and Windows using the firmware's boot manager. You'll have to figure out which F key brings up the boot manager. On my Intel NUC it's F10, *shrug*. -- Chris Murphy