Booting a late-2013 MacBook Pro 11,1 from an external USB hard-drive

[jrussell88]

I'm dual-booting a late-2013 Macbook Pro with Ubuntu 14.04 x64 (vmlinuz-3.13.0-24-generic) and OSX 10.9.2 with Refind. This worked well after I installed Refind's ext4 driver.

I also have the hard-drive from my previous laptop on a USB external drive with copies of Windows and Ubuntu on separate partitions which I'd like to boot on the Mac. I can mount these partitions on OSX or Ubuntu, but as Refind didn't recognise the installations I used Gdisk to change the disk to GPT.

After that, Refind recognised the existence of the external Ubuntu and Windows installations, but doesn't give any information about the kernel and shows a penguin icon for Ubuntu. Trying to boot this leads to a pause then a blank screen with the message:

No bootable device - insert boot disk and press any key

I added a stanza in refind.conf referring to Ubuntu by UUID, and I added a refind_linux.conf to the Boot folder in the Ubuntu 13.04 x64 partition on the external drive, but this made no difference:

"Boot x64 13.04 with standard options" "ro root=31b998f7-0607-40f3-ba7f-67f297d79a2d quiet splash"

Can anyone suggest where I've gone wrong, or how to get it working?

Thanks.

[joevt]

It sounds like your current installation (internal drive) is booting from EFI (hence the need for the ext4 driver).

From what you're saying, the USB drive was originally MBR only (using BIOS booting), and you converted it to GPT. You need to make it a hybrid GPT-MBR for BIOS booting to to work.

Even if the USB drive's MBR is setup properly, booting from it using BIOS might not work on some Macs (or any Macs - I'm not 100% sure - it may work on newer Macs when you first install Windows for example and the install media is a USB stick or DVD).

It might work if you setup EFI booting on the partitions of the USB drive.

[Roderick W. Smith]

Booting from external drives, particularly in BIOS mode, is a bit iffy on Macs. I'm afraid I don't fully understand the problem, and I lack the right hardware to investigate it myself, so I can't be of a lot of help in overcoming those problems.

Linux you might get booting by copying the kernel from the external drive to a partition on the internal drive. You could use the ESP for this or create a separate /boot partition for the external-drive Linux. So long as this is set up correctly (with a suitable refind_linux.conf file), it should work.

Before you try this, though, try hitting the Esc key in rEFInd's main menu. That triggers a re-scan, which sometimes picks up volumes that are shy about showing themselves when rEFInd first launches. If this works, setting scan_delay in refind.conf usually works around the problem. Setting it to 1 second is usually adequate.