Remote update with EPCS128

Open the .rbf file using a hex editor. There are numerous hex editors available for free. Some text editors have a hex mode where you can view in hex. Search the internet for "hex editor" and you will find many. Regular notepad in windows does not have a hex mode.

The .rbf file has nothing but the binary for the FPGA. No header or anything. I would recommend writing byte by byte that way you don't have to deal with endianess and potentially only have to reverse the bit order within each byte before writing it to the EPCS128. You will easily spot that if you do the test that I suggested above.