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Shawn's Guide to Converting SNES Files to GDSF3 Format


This document outlines the methods I use in order to convert 
SNES files so that they are playable on my Game Doctor SF 3.  
I would assume that these techniques would also work for the 
GDSF6, GDSF7, or the Professor SF 2, but they have not been 
tested on these systems.  Please keep in mind that I use floppy 
disks for my collection, so my largest possible file size is 
12 Mbit.  The reason this is important is due to the fact 
that split files are handled differently than single files.  
I am able to successfully convert almost all files.

Utilities Required

You will need a PC in order to convert these files.  I'd 
recommend having at least 8Mb of free hard drive space in 
order to temporarily store the SNES files.  I use the 
following utilities:

- uCON v1.41 by Chicken&chp - a file conversion utility that 
is quite useful, but there are some quirks that must be 
known about it in order to convert properly.

- Super Famicom/NES Tool v1.04 by BASELINE 2091 - a file 
conversion utility that is limited, but performs some roles 
that uCON can't.
- 1.6Mb Disk Bios Patch v1.1a by Quazar - this little 
program lets your 1.44Mb floppy drive read from and write to 
your floppies formatted to 1.6Mb.  

- creator unknown - this .ips file is used to fix a GDSF 
problem with 32 Mbit games using BRAM.  

If you require any of these files, you can e-mail me at  

The First Step

Place the files listed above in a directory.  Run 
if you want your floppy drive to be able to read from and 
write directly to 1.6Mb floppies.  Place the file(s) you 
wish to convert in that directory.  Let's assume the first 
file is called filename.1, but the name is unimportant.

Type "ucon filename.1".  This will display information on 
that file.  The important thing to notice is the HiROM Game 
line.  It will read "Yes" or "No".  

Also, note the Image Format line.  If it reads "Game Doctor 
SF III", then the file is already in the right format, and 
all you'll need to do play it is ensure that the files are 
named in the format "SFxxxxxA", "SFxxxxxB", etc.  If it is 
not in GDSF3 format, then keep following the instructions.

If the game is split into more than one file, you must join 
these files.  Now it is important that the files are named 
in the format "filename.1", "filename.2", etc.  Enter the 
command "ucon j filename.1"  This will create a single 
joined file, named "filename.smc" if it is a lo-rom file 
(ie. if the HiROM line said "No" earlier) or "filename.fig" 
if it is a hi-rom file.  If you are really short on hard 
drive space, it is safe to delete the split files now.  

Now enter "ucon filename.fig" or "ucon filename.smc" 
(depending on what file was created in the previous step), 
and note the File Size line.  Hopefully, this will be either 
2.00, 4.00, 8.00, 12.00, 16.00, 20.00, 24.00 or 32.00 Mbit.  
If the file size is an odd number of megabits (ie. 16.12 
Mbit), then a console group probably added an intro or a 
trainer, which can seriously screw up your converting 
attempts.  You still might be able to convert (and some 
games don't even need converting), but you may be out of 

Now that you are equipped with the file size and if the game 
is hi-rom or not, go to the appropriate section below to see 
how to convert.

Lo-rom and 12.xx Mbits or less

There is no need to convert these files.  They are playable 
on your GDSF3.  Just rename the single file to "SFxxxxx".  
Intros and trainers should not be a problem for these games.

Lo-rom and 16.00 Mbits

Enter "ucon c filename.smc". Make sure that you do not 
specify an output file name (this will make your life 
easier).  This will convert the file into "SFfilen" in this 
case.  Then enter "ucon s SFfilen", which will create two 8 
Mbit files named "SFfilenA" and "SFfilenB".  I recommend 
renaming  these files to "SF16xxxA" and "SF16xxxB" so that 
the GDSF3 knows to stop asking for files once the last file 
is loaded.  These two files are playable on your GDSF3.

Lo-rom and 24.00 Mbits

This is where we have to use stool.  Enter "stool m 
filename.smc".  This will create the file "filename.mgd".  
Now we have to split this file.  Enter "stool m -s? 
filename.mgd SF24xxx".  It will then prompt you for the file 
sizes.  Make three files of 8Mbits each.  This will make the 
files "SF24xxx.1", "SF24xxx.2" and "SF24xxx.3".  I believe 
the GDSF can load these file names, but I always rename mine 
to "SF24xxxA", "SF24xxxB" and "SF24xxxC".  (By the way, I 
believe if you have a lo-rom game of any size on your hard 
drive, it can be played without converting if it is all in 
one file)

Lo-rom and other file sizes > 16.00 Mbits

I've only run into one of these:  a 20.00 Mbit lo-rom file.  
I believe the process would be the same as the 24.00 Mbit 
process, but for the file sizes, create as many 8 Mbit files 
as possible, and have a shorter last file if necessary.  

Hi-rom and 4.00, 8.00 or 12.00 Mbit

Enter "ucon f filename.swc".  This will create two files 
named "SFfilenA" and "SFfilenB", each of half the size of 
the original file.  Just load the first part into RAM Area A 
(or C) and the second into RAM Area B (or D).

Hi-rom and 16.00, 20.00, 24.00 or 32.00 Mbit

Enter "ucon f filename.swc /3".  This will create as many 8 
Mbit files as needed, named "SFfilenA", "SFfilenB", etc.  A 
20 Mbit hi-rom game will convert into three 8 Mbit files, 
and there is nothing that can be done about that.  

Hi-rom and 32.00 Mbits and uses BRAM

If the Game Pak Type line reads "ROM and Save RAM" for a 
32.00 Mbit game, I find that I will not be able to save 
during the game.  So, after converting the game, I would 
take the first file "SF32xxxA" and enter "ucon i SF32xxxA 
savefix.ips".  This will change a couple of bytes in the 
header, and I should be able to save without a problem now.  

Hi-rom and a weird file size

You might be out of luck here.  I suggest entering "ucon p 
filename.swc" which will pad the file size to the next 
highest megabit.  Then I would try "ucon f filename.swc" or 
"ucon f filename.swc /3" and hope for the best.


And that's all (!) there is to it.  As far as I know, 8 Mbit 
GDSF files cannot be broken down into two 4 Mbit files, 
which is kind of annoying since most of my disks are only 
2/3 full because of that limitation.  

If you have any questions or recommendations, please let me 
know.  I think I'll slap this on my home page at

I hope this helps.


Shawn Stackhouse                             "It's not the band I hate,
3B Actuarial Science - U. of Waterloo         It's their fans."                - Coax Me     Sloan