On Tue, Apr 19, 2016 at 5:42 AM, Jerry Geis geisj@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*.