I understand you're looking for the 鈥� specifically the one that upgrades a Mac Pro 4,1 (2009) to 5,1 (2010) to support newer CPUs and faster RAM.
Here鈥檚 the you need: 鈿狅笍 Important note before you start The original official Apple tool is no longer hosted by Apple. The community-maintained version is available, but you must be careful where you download from to avoid malware. 鉁� Safe download source The correct, working tool is called "Mac Pro EFI Firmware Update 1.5" 鈥� but the patcher version for 4,1 鈫� 5,1 is available from trusted Mac community forums: Mac Pro 2009 To 2010 Firmware Tool Download Fixed
馃敼 (definitive guide + download link) Search for: "Mac Pro 4,1 to 5,1 firmware upgrade" 鈥� user "Rominator" or "Macschrauber" typically provide verified, clean copies. I understand you're looking for the 鈥� specifically
