"Boot Linux from unknown volume"

[Trevor]

EDITED to include more details:

Macbook Pro, Mid 2012. I had been running dual boot OS X Mavericks with Ubuntu 14.04 (using rEFInd 0.8.4), and everything was working fine. The rEFInd menu would let me choose between OS X and a Linux icon which, when chosen, would first present me with the grub menu (Ubuntu, a couple kernel versions, safe mode, memory check,...).

Then I upgraded to Yosemite and rEFInd 0.8.6. Now the rEFInd menu shows OS X, a Linux icon with text "Boot Linux from unknown volume", and three Ubuntu icons with three different kernel versions of Ubuntu 14.04 ("Boot boot\vmlinuz-3.13.0-45-generic from 57GiB ext4 volume", etc.).

OS X boots fine. Choosing the Linux icon results in "No bootable device: insert bootable drive...". Choosing any of the other three Ubuntu icons results in a black screen during system initialization/kernel load (possibly a video driver issue?).

1) How can I see the grub menu when I choose to boot one of the Ubuntu kernels? I have tried 'c', "shift", and "esc". Or how can I load a terminal before it tries to load the advanced drivers?

2) Any suggestions for how to get my rEFInd menu back to how it was when everything was working (just OS X and Linux/Ubuntu icon).

Any help is appreciated! Thanks.

[Roderick W. Smith]

First, my suspicion is that the new Linux kernel entries have appeared because when you installed 0.8.6, install.sh detected your Linux partitions and so installed the ext4fs driver. You can get rid of those entries by deleting said driver -- but a better option may be to figure out how to get those options to boot. (More on that shortly....)

Could you please try version 0.8.5 and report whether it can boot your (presumably BIOS-mode) GRUB? That will help me isolate the cause of the problem, since there were changes to the Mac BIOS-booting code in both 0.8.5 and 0.8.6. Also, how many physical disks do you have, and if more than one, on which disk is your Linux installation located?

As to booting Linux via the kernel options, it's not clear from your description if Linux is failing to boot at all or if it's booting but you're just seeing a black screen. If the latter, I'd suggest either just living with it or adjusting the kernel options. You can adjust kernel options by editing /boot/refind_linux.conf in Linux. If that file is absent, create it by running the mkrlconf.sh script that comes with rEFInd. (Run this in Linux, not in OS X.) You can try playing with the quiet splash options, and perhaps find others via a Google search for your symptoms.

If Linux is failing to boot at all, then I recommend you hit F2 or Insert twice in rEFInd after you highlight the Linux kernel option. This will open a simple text editor in which you can adjust kernel options. If quiet splash is present, delete those options and try again. You can also try adding options, but you should try a Google search on your symptoms and model to try to find something relevant.

[Trevor]

Thanks for the response.

Version 0.8.5 seems to have the same end result. Only difference is that the Linux icon has the text "Boot Linux from Fat volume" instead of "unknown volume", but it still results in "No bootable device...". Not sure what rEFInd is seeing that creates that icon though. I think the only FAT32 partition is the EFI.

I'm now convinced that Ubuntu is booting when I choose any of the three Ubuntu icons, but there is a graphics driver problem that I need to address. Now if I could just get to the GRUB menu I could fix that. To answer your other question, I only have one physical disk.

I'm currently messing around with the refind_linux.conf file. NO luck so far.

Thanks again.

[Roderick W. Smith]

I applied some late rEFIt patches to 0.8.5 that didn't make it into the original rEFInd. These patches are intended to fix problems when booting BIOS-mode boot loaders from other than the first physical disk. Does your system by chance have more than one disk? If so, where is Linux installed, and where is the BIOS-mode GRUB installed? It could be that this rEFInd change is causing device assignments to change (from GRUB's perspective), which might account for the problem; or perhaps the rEFIt/rEFInd fix is confusing the firmware, trading one problem for another.

You can edit the Linux kernel options by hitting F2 or Insert twice after highlighting the option (before pressing Enter). This will give you some of the functionality you'd have at a grub> prompt, so you might give it a try if you think you know of kernel options that might help.

[Nap]

(retina MacBook Pro 2014 with 10.10.2 single SSD)

I have a similar issue with the Linux Icon, but I've fixed the multiple Ubuntu Icons.

My refind.conf file is on my EFI partition (which is hidden by default). I needed to use 'defaults write com.apple.DiskUtility DUDebugMenuEnabled 1' in a terminal, then in DiskUtility 'Debug->Show every partition' before I could mount the EFI partition (through DiskUtility). The refind.conf file is in the /EFI/boot folder on that partition.

Each of the Ubuntu icons is generated for a particular kernel version. I edited my refind.conf file by specifying 'dont_scan_files vmlinuz-3.16.0-30-generic'. So now I only get an Ubuntu icon for the kernel version I want.

But I'm stuck on getting rid of the Linux icon. Pressing F2 twice shows a blank editting area. When I boot from it, I don't get any failure messages, but my CPU goes into some sort of busy loop that causes my fan to rev up.

I can't figure out how to remove the Linux icon.

[Roderick W. Smith]

Nap, I can't tell from your description what the Linux icon is, but I suspect it's a BIOS-mode boot loader. You can remove the icon by any of the following means:

• Disabling BIOS-mode booting (using the scanfor option)
• Using the dont_scan_volumes option in refind.conf
• Removing the relevant boot loader code by using dd. This is tricky and dangerous, so I don't recommend it unless you're an expert.