Download The Guardian Legend MMC5 Patch ROM Hack

The Guardian Legend Mapper Conversion
From UNROM to MMC5 (from UNROM to Mapper 5)
by Dracula X

RELEASE DATE: September 26, 2016
Last Modified: May 23, 2020

In order to get this to work, patch it to an unmodified ROM first and then patch one of the hacks to the file.
You can now apply any TGL hack to this hack including "The Guardian Legend WORLDS" Utility.

Bankswitch:
To use it, all you have to do is select a bank and jump to it.

LDA bank_number
JSR $FFC0

You can also use Nflate from http://www.romhacking.net/ Utilities to expand the ROM up to 512kb.

You can now use free RAM space at $5c00 to $5fff and $6000 to $7fff for cool or new stuff.

Bankswitching:
to bankswitch from $8000 - $Bfff and from $C000 - $ffff, here's how to do it:

LDA bank_number
JSR $FFC0
JMP New Location

or

LDA bank_number
JSR $FFC0
RTS

New location would be $8000 or $A000 etc... Bank 08 would be at $20010.

Have fun!

This patch also works for:
Guardic Gaiden (Japan)

This patch does not work for:
Guardian Legend, The (Europe)

Hacks Supported:
All!

Hacks not supported:
MMC3 Hacks!

Use Delta Patcher to patch the xdelta file to the ROM. 
Ignore the checksum and then patch the file.

Changes for this version 1.2b:
Moved the MMC5 Setup to $3FF10 in the ROM file and fixed the reset game code.
Removed the code from $FFC9. 

Changes for this version 1.2a:
Correct the MMC5 setup since I understand it now.

Changes for this version 1.2:
Fixed the bankswitch code that cause the player to jump to the top of the screen
in Fighter Shape mode and other causes to the game.

Changes for this version 1.1:
Now works with BizHawk and Mesen
Added Extended RAM mode ($5104)

Credits:
Rockman: for info on how to convert the mapper!
Disch: for his mapper docs!

Non Supported Emulators:
Nintendulator
RockNES
VirtuaNES