Before you go to that trouble make sure that you are ending up with a CD-r with the following file in the root of the disc: 100601_01_UP5000_XAA.RUF if you still have the .ISO extension on the file when burned to the disc it won't work.I am ending up with a disc named FW and then that single file in the root of the disc. Kinda hard to tell without an actual disc to write on. I get that result both if I mount the ISO to my mac or I burn a disk image with Toast and then mount it (essentially the same thing, just an extra step to simulate the writing of the disc).
Also I'm not sure about the ISO burning software you are using for this. Maybe someone else out there can give you some pointers. Neither of those names rings a bell, but you would think they both would work. I remember my Tosh A-35 only liking discs that I burned with Apple Disc Utility and ones made with Toast would not work (I normally use Toast and my first attempt failed to yield a disc that would update the player). I haven't seen where the Sammy 5K is all that picky about the ISO burning software you use as long as it is done properly. Also all the other players (LG, Sony etc.) that I have updated seem to work with either program also.
There must be some trick to getting it to work properly from a PC since if I recall right in 2010 when 1.5 and 1.6 came out a bunch of folks here requested update discs from Sammy that had the .ISO file just written to the disc (as data) and they did not work either. Those that could not burn a disc themselves and got further burned by Sammy (sorry couldn't help myself) with bad discs contacted me and I made them discs that did work. I recall one person needing a CD-r/w after I sent them a CD-r that did not take.
If you search/browse this thread back a couple years or so Vinnie posted pointers/instructions on how to burn the discs from a PC.