To repack or port a TWRP custom recovery , you essentially need to combine the kernel and device-specific files from your stock recovery with the TWRP user interface files. Core Tools Required Android Image Kitchen (AIK) : A Windows-based tool used to unpack and repack Stock Recovery Image : The original recovery.img from your specific Vivo Y71 firmware. Base TWRP Image
To repack a TWRP image for your device, you will generally follow this workflow using tools like Android Image Kitchen: twrp vivo y71 repack