How can I get Windows to install in Legacy (BIOS) boot on my mid-2012 MBP I've got a 13" mid-2012 MBP running OS X 10.10.3 Yosemite. I've recently repaved it with a fresh install and now I'm getting round to Bootcamp`ing it. I've installed Windows 8.1 in EFI boot mode and discovered the well documented issue with the sound card not working. Following various online guides to install Windows in legacy boot mode, I've held option at boot and selected "Windows" on the USB thumb drive that Bootcamp Assistant created but all I get is a black screen with a white blinking cursor. I've left it for 10 minutes but still nothing (some reports say it boots to the installer after a while).

I believe the disk is hybrid MBR (due to Bootcamp Assistant), here's the output from fdisk

Gregs-MBP:~ greg$ sudo fdisk /dev/disk0  
Password: 
Disk:   /dev/disk0  geometry: 60801/255/63 [976773168 sectors] Signature:   0xAA55   Starting       Ending  #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] &lt;Unknown ID&gt;   
2: AF 1023 254  63 - 1023 254  63 [    409640 -  486812704] HFS+   
3: AB 1023 254  63 - 1023 254  63 [ 487222344 -    1269536] Darwin   Boot   
4: 0B 1023 254  63 - 1023 254  63 [ 488493056 -  488280064] Win95 FAT-32


How can I get Windows to install in legacy boot mode?

Note, I previously had Windows 8.1 working fine (audio and everything) and if I remember correctly I just ran Bootcamp Assistant and followed the instruction, no trouble.
Well I've finally found an answer: just use a Windows 8 install CD ROM with the standard 'install Windows 7 or later option' selected. Do not install Windows 8.1. It seems the problem is with the latter messing around Boot Camp normal procedures rendering audio and some other components unusable.

Where my MBP 13″ mid 2012 wouldn't complete my installation with Boot Camp before, now the installation starts in legacy via the CD, it just flows and at the end of it I get to install my version of the Boot Camp drivers found on the net and audio works fine.

What might have influenced the whole process was that I accidentally erased my whole disk, had to start from the recovery over the internet (Command + R at startup) and reinstall Yosemite and my files through my Timemachine backup). Maybe it fixes something with my old recovery and EFI partitions, but I can't know for sure.