the bootloader that you need is version 5.8
unfortunately, i have version 5.9 and the downgrade doesn't support that version yet, which is a complete bummer. also, i currently don't know how to downgrade the bootloader!! UGHH!! this is frustrating, if it's not the baseband, it's the damn bootloader!! I might was well just buy a rebel sim card and unlock it that way. saves me a headache & time.