Insert As Is the RebarDXE.ffs using latest available mmtool v5 to GUID A0327FE0-1FDA-4E5B-905D-B510C45A61D0, save, then copy that bios to your flash drive.
Go downgrade your bios to any version before agesa 1.2.0.0, then after you went back to an older agesa, update the modded bios using qflash just like what you did when downgrading your bios.