Hello friends,

So I finally figured it out, I managed to remap the functions of my MFX ESU Decoder using a Control Unit 6021 without the need for the Lokprogrammer Hardware or a Mobile/Central Station.
Specs:
- Locomotive Marklin 3795.10
- Decoder installed ESU Loksound V4 MFX 64407
- Control Unit 6021

You will have to get the new CV code value mappings and reprogram them into your decoder, it was no simple task, here is how I did it :
1. First download and Install the latest LokProgrammer PC Software from here. I chose the latest version to download Date: 27.10.20, Version: 5.1.0.

2. Once installed (it's free but works only on PC). download your file file for your ESU Loksound from here . In my case it's "LokSound V4.0 Family, LokSound Select " and then I did a search for "64407" and downloaded the corresponding sound file (see screenshot)



3. Next launch the software LokProgrammer select "Open an Existing Decoder Project" and open the sound file you downloaded in Step 2, see screenshot:



4. Once you open it go to "Function Mapping" notice you will see the functions mapped by default on your loco, when you press a function button you get the sound/function corresponding to what is shown in the table (see screen shot)



5. Remap the functions buttons to your choosing. For more on how to remap/use function mappings here's a good video. In my case example I wanted the loco to make steam on F3 instead of the announcement #2 sound (see screenshot)



6. You can also modify any other function mapping of your choice; i.e. dimmable headlights, sound on reverse, max speed...etc. Once you are satisfied with your customizations. go to the the Tools Menu > select Show Changed CV's (see screenshot)



7. Once you click on that you will get the code of CV's that need to be changed to new Values (see screenshot)



8. Now using your 6021 you will need to input these CV values into your decoder. This is the tricky part.
a. Remove any loco from the tracks and place only the loco you wish to reprogram
b. On the 6021 Control press GO + STOP at the same time until 99 comes up
c. Press STOP
d. Enter your loco digital address in my case it's 03 (default is 80 if you're not sure) Turn the knob to the REVERSE position while holding press GO
e. You will now notice the headlights of your train are flashing meaning it's ready to program
f. Enter "08" Press REVERSE Enter "08" again and press REVERSE; this will make sure you reset the decoder to the original default settings (see screen shot from step#4 for what those settings are)
g. Your train is now set to the default decoder settings.
h. Turn OFF the 6021, unplug power wait for 10 seconds and replug
i. press GO + STOP at the same time until 99 comes up
j. Press STOP
k. Enter your loco digital address ("03" if not "80" or whatever your address is set to)
l. While holding in REVERSE position press GO, train headlights will begin to flash, now you are ready to input the CV addresses
m. So there are 2 mode of entering CV addresses the Short Mode and the Long Mode see the Loksound Manual here in my case it's the Loksound V4.0. It explains entering the Short Mode in sections 8.2.3.2 and Long mode in section 8.2.3.3
n. So if you look at CV list we generated (see step#7) it's made of short mode CV (index CV's) and Long mode and I am going to explain how to input them using your 6021. See screen shot


o. Remember from step "L" your Headlights are still flashing waiting for CV to be entered: so here we need to set CV 31 = 16, so on your 6021 enter "31", click REVERSE and then enter "16" click REVERSE the headlight will turn solid light for a sec and then flash again. Next we need to enter the second Index CV32 = 2. on your 6021 enter "32" click REVERSE and then "02" click REVERSE your headlights will turn solid light and then will flash again.

p. Now you need to enter the Long Mode CV's we have a a total of 8 to enter. These are made of 3 digits but your 6021 can only accept 2. so Lets starts with the first one this is how you do it

q. Enter "07" click REVERSE enter "07" again click REVERSE notice how your headlights will begin to flash faster, they are now in long entering Mode.

r. We begin with the first one CV362 = 4. Remember the 6021 does not accept more than 2 digits and no 00 and no 99. so you have to enter it in double digits this is how. To set CV 362 = 4. You enter "36" click REVERSE (here you will get long headlight flash-short) "02" click REVERSE (long Headlight flash -short-short) "80" click REVERSE (long Headlight flash -short-short-short) "04" click REVERSE Solid headlight Flash it is now registered.

s. So in simple terms the long mode always has 4 inputs of double digits: "XX" REVERSE "XX" REVERSE "XX" REVERSE "XX" REVERSE
So when you want to set 362 to 4 meaning "36-02" to "00-04" and to do that enter"36" REVERSE "02" REVERSE "80" REVERSE "04" REVERSE. NOTICE instead of 00 we entered 80 remember because the 6021 does not accept 00. And for the second line CV363 = 64, it would be "36" REVERSE "03" REVERSE "06" REVERSE "04" and so on. More Details in manual on page 33 in section 8.2.3.1 "Please bear in mind that the 6020/6021 only permits you to enter values from 1 to 80. The value 0 is missing. Always enter „80“ instead of „0”"

t. and then you go through the remaining list of CV codes and there you have it! your customized functions are mapped and programmed into your loco using a good old school 6021 unit.

That should Save you some money on buying a Central/Mobile station and time on figuring it out, and you get to keep using your 6021 if you have one. I personally love it.
I hope you find this beneficial and helpful, of you have any questions or comments please feel free to ask. Thank you all again for your help.

AH,