[OT] MacPro 4,1 quad upgraded to 5,1 hex: memory missing

[zephonic]

I'm baffled here, hope someone can help.

 

I did the netkas firmware tweak that turns a 4,1 MacPro into a 5,1 and just replaced the old W3520 CPU with a W3680.

 

Thing is, I have 3x8GB 1333MHz modules in slot 1,2,3 but after the CPU swap the system doesn't detect the module in slot 1 anymore. I tried reseating it, nothing. I moved the DIMM to slot 4 where it was detected and OSX prompted me to put the modules in slot 1,2,3. Put it back in slot 1, still nothing.

 

I put the old CPU back in, same thing, the DIMM in slot 1 is not detected.

 

I'm really worried, because I need this machine to work and can't afford a new one. FWIW, I already did the NVRAM reset. Also, other than the missing memory module, everything works fine, and the machine geekbenches around 15000.

 

Anybody know what is going on here? Thanks in advance.