I'm trying to speed up the boot process in my iMac as much as possible.
With Ubuntu 14.10 and kernel 3.16 I succeeded in booting the system by creating a small HFS+ partition, to be used as the system efi's one, copying the kernel and the initrd image to it and blessing that file/folder using efibootmgr and hfs-bless.
The system used to boot perfectly. No need for grub.
But after upgrading to Ubuntu 15.10, X fails to detect my graphic adapter. I can boot perfectly if I use GRUB. Viceversa, if I bless the vmlinuz.efi executable instead of the GRUB's boot.efi, the system boots but X fails to start. It doesn't recognize the Graphic card. In the Xorg.0.log file it is written that KMS is enabled successfully but no card is detected.
So my question is: why the card is detected if booting thru grub and not if booting the kernel directly? I repeat, with Ubuntu 14.10, this worked perfectly.
How can I debug what Xorg is overlooking if booted without grub?
Thanks
