If renaming the file results in an error (like "signature verification failed" or "invalid sparse file"), the file might be wrapped in a specific container format. You can use a Hex Editor to verify this.
When you create a "Nandroid" backup using TWRP, it saves each partition as a separate file. The boot.emmc.win file is a raw image of your . boot.emmc.win to boot.img
boot.emmc.winboot.emmc.win.md5 (optional, but recommended to verify integrity)If your TWRP backup was compressed, the file might be named . Use a tool like 7-Zip or WinRAR to extract the .gz file. Once extracted, you will have a boot.emmc.win file. Follow the Method 1 renaming steps above. Method 3: Extracting via ADB (Alternative) The Ultimate Guide: Converting boot