15" late 2011 MBP doesn't boot Yosemite

[A1ik]

Need some help debugging the problem with my MacBook Pro.

Any time I start my MacBook Pro I can hear the startup beep, see Apple logo, then grey screen with a progress bar. The progress bar gets stuck at about 25% and then nothing happens.

Interesting enough I can login to that MacBook Pro from another computer using ssh. Here are some details:

i7:log alik$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.10.5
BuildVersion: 14F1021

i7:log alik$ uname -a
Darwin i7 14.5.0 Darwin Kernel Version 14.5.0: Tue Sep 1 21:23:09 PDT 2015; root:xnu-2782.50.1~1/RELEASE_X86_64 x86_64

The full Apple Hardware Test (AHT) doesn't show any problems.

Tried resetting NVRAM - no effect

Tried booting in Safe Mode - the same result.

Tried to recover the system from both internet and USB storage: after some initial loading the screen turns grey and nothing else happens.

Replaced both HD and RAM - with no effect.

A fragment of /var/log/system.log is attached to this post.

Please, advice!

Thank you,

--Alik

 

[A1ik]

I've just learnt that the problem is due to a faulty GPU chip. Apple recognizes this as a manufacturing defect and fixes it for free. This silly procedure disables GPU acceleration and makes your MBP somehow usable:

It worked for me. But my graphics is now painfully slow. I am going to book a service appointment with Apple now...