legacy mode on mid-2015 retina MacBook Pro

Question

mefromnic Author

Level 1

4 points

legacy mode on mid-2015 retina MacBook Pro

Hi All,

I'm having difficulties to enable legacy boot mode on my retina MacBook Pro mid-2015.

sudo bless --device /dev/disk0s4 1 --setBoot --verbose --legacy

EFI found at IODeviceTree:/efi

Firmware feature mask: 0xFC03FF3F

Firmware features: 0xFC03F536

Legacy mode NOT suppported

Legacy mode not supported on this system

Is this really not supported?

The legacy mode is essential for me to boot my work system.

If I could only enable Legacy mode and boot my MBR based USB stick with grub4dos, it would solve all my problems.

I've tried to use refind but it didn't help. Seems like it is new Mac Book Pro limitation. The previous one mid-2014 worked perfectly with same disk image and USB key.

More on this is here:

https://sourceforge.net/p/refind/discussion/general/thread/90347215/

Thanks in advance for help.

MacBook Pro with Retina display, OS X El Capitan (10.11.6)

Posted on Aug 5, 2016 9:34 AM

Reply

Answer 1

mefromnic Author

Level 1

4 points

Aug 6, 2016 1:57 AM in response to mefromnic

Further research shows that this is all related to the new MacBook Pro firmware:

MacBookPro11,5 with firmware MBP114.0172.B09

https://forums.kali.org/showthread.php?31275-MacBookPro11-4-and-rEFInd-impossibl e-to-boot-kali

http://blog.twocanoes.com/post/130271331763/how-el-capitan-boot-camp-is-affected -by-apples

https://sourceforge.net/p/refind/discussion/general/thread/90347215/

Is there really no way to boot legacy USB/MBR based stick? This is huge limitation introduced silently on new Mac.

To make it even worse, I've got the new one as replacement for the old one from Apple and it makes it even worse for me as it impacts my work system (can't boot it anymore), booting via VirtualBox/VmWare is no joy as it goes slow and super warm.

Might need to move away from Mac... simple things get all too complicated.

Reply

Answer 2

Loner T

Level 9

59,566 points

Aug 6, 2016 6:23 AM in response to mefromnic

Stick with 2014 or 2013 Macs. 2015 Macs no longer support Legacy BIOS mode, because CSM-BIOS was removed from UEFI Macs. You should also consider returning the 2015 Mac and buying a refurbished 2014 from Apple.

mefromnic wrote:

Is there really no way to boot legacy USB/MBR based stick? This is huge limitation introduced silently on new Mac.

Do you need to boot a legacy OS or do you need to support for a MBR USB boot? Most modern OSes also support EFI Boot, unless you want to run WXP or W7. The introduction has never been silent. 😉.

Reply