Latitude E6430 BIOS restore

Good day,

I have a Dell Latitude E6430 that has a corrupted BIOS due to a power failure while it was updating, the battery is dead. I have tried I don't know how many times to restore it to the original BIOS(A09) in order to get it working again, but no matter what, it will not restore. I have followed the guidelines on the Dell websites, I have formatted the USB drive in FAT, renamed the .exe file to BIOS_IMG.rcv and when I press CTRL and ESC and then plug the power supply in it reads the USB drive for a while then just switches off, no activity on screen at all. Can anyone please advise how I can recover this laptop or is it dead?