Flashing/downgrading with bad data port

[old_school_dave]

Hi everyone, My xv6800 (dcd3.01) has come up with a bad data/charging port. It needs to be sent in for replacement. I've searched the boards and it appears the method for me to go back to stock vz is via sd card. The issue I don't see addressed is how one can downgrade the bootloader. Can this be done via sd card flash somehow? Maybe via bluetooth sync? If none of these will work, is there any other 'prepping' the phone should get before sending back? Thanks!