I suppose there are a number of ways to convert from b75 to PUFF but for me the easiest way is as follows.
1) load ANY b75_m bin to the receiver so that it can fully boot. You can use the loader you have been using for the b75 bins or use the one I included in the attached file called DSSToybox Fortec Ultra Lifetime Updater.exe. I also included one of my b75 bins chosen at random in case you don't have one but you probably all ready do. ANY b75(lh5) bin will be fine you don't have to use mine but it is there if you need it. Once you can boot your b75 receiver to On or a channel number you can proceed to step 2.
2) use GTRom Loader v27.02 [Pansat2700A - B75].exe and -PUFF-_boot Ver.1.0.1.bin (64K)and load that to the receiver AFTER IT HAS FULLY BOOT and is showing either ON or a channel number on the front display.
while the new boot is loading the display will count from 0000 to 0100 and then reboot. It will then go PUFF PUFF stalling on the last F.
AT THIS POINT YOU ARE CONVERTED TO PUFF BUT THE BOX WILL NOT BOOT BECAUSE YOU STILL HAVE A B75 MAIN PROGRAM BIN LOADED.
So all you have to do is load the new PUFF bin using the same procedure you use to load the b75 bins, and that is.
1) open your loader program (not the GTRom loader you used in the conversion step) I included a loader program that I used before I wrote my own. It says fortec in the title but will also work for pansat 2500. It is called DSSToybox Fortec Ultra Lifetime Updater.exe. I also included my PUFF 201 Femu bin in the attached file pack, but you can use any PUFF bin you don't have to use mine.
2) get the new bin ready to download, connect cables etc. 3) turn off the stb via the back switch 4) turn on the STB from the back switch and click the download button on the loader as soon as you see the first P 5) DONE!
As long as you are using my femu puff bin then you don't have to worry about stopping it from booting the first time (no rolling puff issue). You will have to rescan your sats and channel master does not work properly (not just on conversion bins but on 2700a as well). Also there have been some reports of loss of channel lists after a hard reboot. Hopefully I will be able to remedy this in the future but for now that is where we are at.
If you scan your channels and then you get scrambled or bad channel hit 8282 and set default keys then exit out if that does not fix then try a hard reboot, upon power up all should be good.
SINCE THE NEW FEMU BINS ARE STILL EXPERIMENTAL I SUGGEST YOU KNOW HOW TO JTAG IF YOU USE ANY OF THEM MINE OR OTHERWISE!!!