must boot under rEFInd sub option vmlinuz

Question

So I was having issues controlling brightness on my recent install of Ubuntu 15.1 on my MacBook pro and rashly followed the directions here :

Brightness controls doesn't work on a MacBook Pro 5.5 (ubuntu 12.04 LTS)

after restart I hit enter with the Ubuntu rEFInd partition like normal and I get the normal "boot log" or whatever it is that runs across the screen and then instead of giving me a log in page I get a black screen with a cursor which stops blinking after a few seconds. Pressing and/or holding shift, or F1 or ctl+alt+F1 does not do anything during the boot process.

I do not and never have had a Grub menu on startup while using rEFInd...I am new with Ubuntu so didn't realize I was supposed to have this screen.

However, I checked under my sub options for Ubuntu in rEFInd and I have 4 options: Boot with normal options Boot into single user mode vmlinuz-4.2.0-16-generic.efi.signed: Boot with normal options vmlinuz-4.2.0-16-generic.efi.signed: Boot into single user mode

Using vmlinuz-4.2.0-16-generic.efi.signed: Boot with normal options, I can boot into Ubuntu fine. But I have no idea what exactly this option is? It has all the same settings and preferences I had in my normal Ubuntu. So what happened? Do I just boot into this sub option every time I want to boot Ubuntu? and I still have no control over my brightness. My apologies if this encompasses many subtopics in one. Maybe I need to totally start over with my Ubuntu partition and get a Grub screen so in case something like this happens again. I'm not sure where to go from here.

Edit I used boot-repair and now have Grub. Booting Ubuntu now gives me a brief purple screen, flashes Ubuntu, flashes 5 red dots and goes to black screen. Pressing e in Grub and changing "quiet splash" to "nomodeset" gives me a brief purple screen and then goes to black.

Answer 1

First, GRUB is just one of several boot loaders for Linux. You can swap it out in favor of something else if you like; it is not required, although it is the default boot loader for Ubuntu. For EFI-based systems, see this page of mine, which describes several EFI-mode boot loaders, as well as related information. rEFInd is a boot manager, which means it shows boot options, but it is not technically a boot loader. The way you had been booting used rEFInd and the EFI stub boot loader, which enables the kernel to act as its own boot loader. This is a perfectly workable method of booting Ubuntu. In sum: Installing GRUB was unnecessary for you.

Second, the rEFInd sub-menu with the four options you note enable you to launch two kernels, each with two sets of options (minimal and single-user). One of your kernels was not working, probably because you hadn't installed necessary proprietary video drivers for it. You could easily boot with the older kernel that did work. In Ubuntu, you could type sudo touch /boot/vmlinuz-4.2.0-16-generic.efi.signed (if that's the kernel that workd), which should make it the default option. In theory, installing a new kernel should install the necessary video drivers for it, but it sounds like that didn't work for you for some reason; or maybe the drivers for the new kernel were buggy. The question and answers you referenced (here) fixed the video driver issue for you. Installing GRUB was not necessary, and might or might not be preferable or create new problems.

If GRUB is currently your default boot manager and you want to go back to rEFInd, you can re-install rEFInd in whatever way you did before; or you can run the new refind-mkdefault script. This script is not yet part of rEFInd, but will be included in the next release. In the meantime, you can download it (click the "download this file" link) and type sudo python3 /path/to/refind-mkdefault to run it, changing /path/to to the appropriate path.

If you prefer rEFInd but want the purple Ubuntu splash screen, you can run the mkrlconf script that comes with rEFInd (run it in Ubuntu), then edit the /boot/refind_linux.conf file to add quiet splash to the boot options for your default boot (if those options aren't already present).