Hi everyone. Just bought a used 2009 MP 4,1 on ebay to replace my dying MP 3,1. I have a wierd issue. The MP was flashed with MP 5,1 FW by the previous owner. But looks like sometime went wrong with the FW updated. The Boot ROM Version reads 140.0.0 instead of 18.104.22.168.0. The front USB ports are not working. The computer behave kind of slow for a 6 core 3.33ghz CPU. I tied to downgrade it back to MP 4,1 but it wouldn't downgrade. I have SIP disabled. tried to flash MP4,1 FW, The front panel light flashes, and then the long beep. Then it went to the FW flashing screen for a split seconds only and rebooted itself. The firmware tool is ok because I have upgraded other MP 4,1 to MP 5,1 wth it before.
Any suggestions? Other getting a used logic board and ebay this one off to let someone else mess with it?
MP 4,1 2009, single CPU, 6 cores 3.33 Ghz, 16 GB RAM, 120GT GPU, Sonnet USB card, Stock BT and WIFI card. OSX 10.12.