On 28/08/2014 19:34, Kevin O'Gorman wrote:
Windows can't be the culprit -- it did not get control between the grub-update and the reboot, and even the first reboot went right to Windows. So there's something that GRUB failed to do.
That's a compelling remark.But, might it be that Secure Boot, which you said you'd enabled, can (irrespective of Grub being there, somewhere) only find Windows as a 'signed' OS so that is the only OS UEFI will load?
[My understanding is that Secure Boot will only load a cryptographically signed OS and that Windows is (so far) the only OS signed with a certificate that is trusted by UEFI.]
If that might be happening, have you tried turning OFF Secure Boot, so that an unsigned [insecure] OS can be booted? BIOS might think that Grub/Linux is untrusted because it is unsigned.
[I'm assuming that UEFI can be used in 'insecure boot' mode. I don't mean in 'Legacy' (CSM?) mode, which, as I understand it, is a different mode.]
If the BIOS and Windows and Grub are - truly - this incapable of getting along on your machine, might it be possible to ask the Windows boot loader to load Grub/Linux, as a W8 boot loader choice? I'm not sure whether that's possible?
Let me say again, I don't have W8.1 but am finding out about this issue (because I intend to get a W8.1 laptop). So what I say may be incorrect, but I have looked at a lot of pages about this and those two suggestions have been mooted elsewhere - though without follow-up indication whether they worked.
Regards, Ron