I understand you're looking for the — specifically the one that upgrades a Mac Pro 4,1 (2009) to 5,1 (2010) to support newer CPUs and faster RAM.
Here’s the you need: ⚠️ 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. ✅ Safe download source The correct, working tool is called "Mac Pro EFI Firmware Update 1.5" — but the patcher version for 4,1 → 5,1 is available from trusted Mac community forums: Mac Pro 2009 To 2010 Firmware Tool Download Fixed
🔹 (definitive guide + download link) Search for: "Mac Pro 4,1 to 5,1 firmware upgrade" — user "Rominator" or "Macschrauber" typically provide verified, clean copies. I understand you're looking for the — specifically