Looks vaguely familiar.
You’ll need to find this driver on the Dell website
Use 7Zip to extract the DELL7455DriverSetup.exe file, and again 7Zip to extract that (I did this originally on linux, where I had funny directory names; if you do it on Windows, you only need to extract the directory thats named “7455”). Inside the 7455 directory, you will find SWI9X30C_01.08.07.00 and SWI9X30C_02.01.03.00. I think that I managed to flash 01.08.07.00 and the matching GENERIC PRI, and never bothered with the 02.01.03 version, and then went to 02.24.03, after rebranding (Note you have to use the older AT!UDPID and AT!UDVID to rebrand).
Its also not clear to me what the difference between the fdt and fdt2 binaries are. did you try both ? I think that I used fdt and not fdt2 (i got that hint from a Russian forum and google translate!)