Upgrading Mac Pro 2009 to 2010. Issues Start point Mac Pro early 2009/ 4 cores Intel Xeon, 2.93 Ghz/ RAM 16 GB DDR3 1066/ Yosemite. Now, I describe what I’ve done and I underline the anomalies that I haven’t been able to solve: 1. Firmware upgrading I run “Mac Pro 2009-2010 Firmware Tool”; I got error 5570. I run the updated and patched “Mac Pro 2009-2010 Firmware Tool” and I got a successfully upgrading: My computer data changed from Macpro4,1 to Macpro5,1/ Boot ROM: MP51.007F.B03 I run “MacProEFIUpdate 1.5.dmg” to update the 5.1 firmware but I got a warning (This software is not compatible with your system). 2. CPU upgrading I took away the 4 core CPU and I install a 6-core Intel Xeon, 3.46 GHz. The system recognized it. 3. RAM Upgrading I replace the four 4 GB modules (1066 MHz/s), with 8 GB modules (1333). The system recognized it but to 1066 MHz/s. I reset PRAM and SMC, what was suposse to update de RAM speed, but the memory stays in 1066 MHz/s. 4. OS upgrading to Sierra I tried three ways to get Sierra from an external hard disk connected to the Mac Pro: - Direct installation from Apple Store. After the first reset, the computer came back to Yosemite giving up the installation. - Installation through a bootable pendrive. Same result. - Installation of Sierra, using a Mac Book Pro 2013, in an external hard disk (that I checked worked fine in the Mac Book). Afterwards I connected this disk to Mac Pro. Mac Pro ignored the change (Preferences instruction), of bootable disk and charged Yosemite back 5. Install macOS Sierra as an unsupported Mac A priori is a contradiction to apply a solution for unsupported Mac to an supported one. Let see. In this procedure there is a step (called “macOS Post Install”), where we have to precise the computer model. The trouble is that the option MacPro5.1 doesn’t exist, what is logic because theoretically this model is Sierra compatible. But, on the other hand, It doesn’t seem a good idea to select the option Macpro4.1 because the computer is not this model already. It seems that the solution must go by finding the way to install Sierra in the Mac Pro as a supported Mac. Source of the problem? SOLUTIONS?