Everyone knows about Return to Dinosaur Land but what not everyone knows is that it will fit onto a single 27C801 EPROM.  The ROM once patched is 16mbit but the second half of the ROM is just padding and can be removed without affecting the game.

For this you will need:
A LoROM donor with at least 16kbit SRAM, I like to use Vagas Stakes or Super Play Action Football
a 27C801 EPROM
Soldering tools

To start off I am using a copy of Super Play Action Football as my donor


Start off by testing the donor to ensure that the PCB is in working order


This is a good game to use it has 64k SRAM and can hold a 32pin chip


Start off by desoldering the mask ROM from the board, there are many ways to do this, I have a Hakko FR-300 desolding gun so that is what I use.
Using solder wick does not work too well because this board uses plated through holes, another method I have used in the past is to cut each leg on the mask ROM then heat the leg with my soldering iron and use tweezers to lift the pin out.


Once the mask ROM is removed it is time to prepare the ROM, I have included an XDelta patch at the bottom of the page that will take care of everything for you, just apply it to a "Super Mario World (U) [!]" dump and you're good to go.  There are 2 patches in the archive, one for a ROM with a header and the other for a ROM without a header.  This patch will apply the RTDL patch, cut the ROM down to 8mbit then swap bin the ROM so it is ready to program to a EPROM.

Keep in mind once applying this patch the ROM is already swap binned and will NOT load on an emulator.

XDelta will tell you if you are using the wrong patch.  Once your EPROM is programmed it is time to install it into the PCB.

I like to start off by connecting a wire to pads 31 and 24 on the PCB


Then bend up pins 24 and 31 on the EPROM and put it into the PCB, make sure the legs are not touching the board as there is a lot of vias to short to


Then solder the EPROM into the board


Then cut and solder the wires to the bent pins of the EPROM


And give the game a test run

Thanks

Legend!

Mrpete, its nice to see some good walkthroughs up. Thanks for the time spent!

Nice thanks for the info! Love these walkthroughs.

I'm glad everyone enjoyed this, I might write up a noob guide with info about picking a donor and EPROM chip ect.

I cannot think if there are any old ball games that would be good to write up.

EDIT: how about a Zelda: GOW+PW multi cart?  who wants to see that?

I would like to see a repro of the game. BS Golf Daisuki! OB Club, there is a header patch to make this work on flash carts without BS support.
Maybe you could check that one?

Thank you for the tutorial above.

That sounds pretty rad.  I could think of thirty people that I could give a gift this awesome to!

I love the look on their faces when they get something like that.  My wifes bff got labyrinth last year for the nes... and no matter how much that game sucks, she loves it heh.

Thanks for writing this up and sharing the patch, I made one earlier tonight and it came out great. Saving money by using one chip instead of two rules too!

Wow this is amazing! Love the idea of saving money and only using one chip! I'm wonder what other games are out there that have been padded and will work for this?

Frankly I find these to be some of the most helpful tutorials. I just ordered my first eprom burner, feel truly inspired. Plans to try this out and the star fox 2 game! I look forward to additional tutorials.

I hope you keep doing these! Good guides are hard to find

If I think of anything good to make a guide for I will.

If anyone has any ideas let me know and I will see what I can do.

What do you use for burning your EPROM? I have been doing a lot of investigation reading reviews but I always trust opinions straight from the source a little more.

I was using a Willem GQ-4X but it did give me some issues.

Now I am using a Xeltek SuperPro 610P, I ordered it from eBay from this seller
http://www.ebay.com/itm/Xeltek-Su...

Does it matter if the donor is slow rom or fast rom? I have a NHL Stanley Cup lying around but it is a fast rom game.

Fast ROM and slow ROM does not matter when picking the donor only when picking the chip that you will be programming.

As long as you chip is rated at 120ns or lower you're good.

Made myself up a copy the other day. Works a treat so thanks for this!

Can't get mine to work, may be a couple of things, after programming it wouldn't verify or it could be I'm just to ignorant to figure out how to create a working RTDL file to program. Can anyone send me a idiot proof file ready for programming? Also if this doesnt fix the problem it could be my tester board I made...

Got mine to work tonight. Thank you so much! My first SNES game down. Going to give parallel worlds ago!

PW is another easy one, if you want to use 27C801 eproms I suggest NBA 95 or troy aikmen football as a donor, they are both lorom with 2 mask ROMs. You just need to use lunar expand to expand the ROM to 16mbit.

So in my trials to get this to work I seem to keep hitting the same issues. 1. I download Super Mario (U) [!], 2. download the Xdelta patch, 3. check Super Mario (U) [!] for header, there's nothing. 4. Swapbin Super Mario (U) [!] using Wasabi At this point this is where I always get into problems. When I try to patch the new swapbinned Super Mario (U) [!] file with the unheadered patch using xdelta I get an error if I don't uncheck the checksum validation box. 5. I uncheck the box and create the new patched Super Mario (U) [!] with return to dinosaur land. 6. I use IpsandSum to check the checksum and fix it cause it needs to be repaired, save the new file thats created. At this point I thought everythings good, the file writes but doesn't verify and when I go to try it, nothing just a black screen.

What am I doing wrong here, I seem to suck at making games with these 27c801 chips

You patch the Super Mario rom first. THEN use lunar expand to make it 2MB. THEN use swapbin. THEN you use the first file, of the 2 created when you swapbin, to program to your chip.

My xdelta patch is made to be applied to a regular SMW ROM no swapbin needed the patch takes care of everything for you, just apply it then program

Yeah, I never used MrPete's patch, I got mine from Romhacking.net I believe. Apparently he has simplified the process.

Mine is only good for repro makers, once patched the file is already swap binned so it will not load on an emulator.

If you want to play on an emulator then you should use the one from ROM Hacking.