mpro Firmware hack grants Nehalem Mac Pros access to Westmere CPUs

Everybody knows that as far as Apple is concerned, the processors it uses in the assembly of its machines are considered to be non-user replaceable parts, and the company often makes use of firmware to limit enthusiasts from performing their own processor upgrades to a Mac. However, it appears that Apple's attempts to halt such upgrades have just met with a setback, for hackers have seemingly discovered a way to force an unauthorized firmware update to the company's line of Nehalem-powered Mac Pros which restores hardware-level compatibility for a certain processor upgrade.

mpro Firmware hack grants Nehalem Mac Pros access to Westmere CPUs

Most hardware enthusiasts who play around with Intel's Xeon processors will be fully aware that the chip giant had made its Westmere CPUs drop-in compatible with the older Xeon processors based on the Nehalem architecture, which has resulted in a smooth upgrade path for many users. Unfortunately, this does not apply to owners of the Nehalem-based Mac Pros released in 2009, as Apple had seemingly chosen not to release an EFI update to enable the use of Westmere processors in the older Mac Pros in spite of their drop-in compatibility. However, it would seem that the hacker community has found a way to help such users circumvent the artificial limitation.

According to a report published by Ars Technica, information about this little trick was posted on the netkas.org forums by a member known as MacEFIRom, who claimed to have finally understood the relationship between Apple's EFI updater and the Mac's booting process. He added that, by making a few changes to the firmware strings and CRC32 checksums,  the updater can be tricked into installing firmware files intended for the 2010 Mac Pro upon reboot.

When that happens, the 2009-model Mac Pro ceases to exist, having been magically transformed into a 2010-model Mac Pro at the push of the power button. And this is also where the fun starts.

Apparently, the installation of the newer firmware grants the 2009-model Mac Pros hardware-level support for Intel's Westmere CPUs. This means that there is nothing to stop users from purchasing two hexa-core Westmere processors (assuming they know where to find them) and transforming their existing overpowered 8-core Mac Pros into an even more overpowered 12-core behemoth. Granted, the upgrade in itself is definitely going to be pricey, but it is still much more affordable as opposed to paying Apple the handsome sum of, say, US$4,999 for what is essentially the same hardware in a 2010-model Mac Pro.

Furthermore, the act of upgrading the Mac Pro with the newer Westmere processors also brings about an added bonus in the form of support for the maximum supported speed of 1333MHz for the system's memory. This is in direct contrast to 2009-model Mac Pros stuck on Apple's stock firmware which imposed a speed limit of 1066MHz on the machine's DDR3 ECC memory, even if the processor  was capable of supporting much higher DRAM speeds. 

Sounds great? Well, don't get your hopes up too soon. After all, Apple enforces a no-nonsense policy when warranty claims are concerned, and suffice to say any user who installs hacked firmware and upgrades their own processors are going to find themselves blacklisted in Apple's little book of infamy.  More importantly, the hacked firmware seems to have the unfortunate consequence of permanently modifying the Mac Pro's device identifier, an act which will render the Mac Pro's restore discs useless until a firmware downgrade is performed. Should the downgrade fail, it is essentially curtains for the user, as only the 2010-model restore discs can be used to reformat the Mac Pro.

Source: Netkas.org via Ars Technica