Metal Gear - SRAM save hack

This hack adds a save function to the Metal Gear game. You no longer need to write down long passwords. Each time a password appears on the screen (after "game over") the cartridge stores it into battery-backed PRG RAM memory. On the password entry screen, press the "start" button to enter the saved password automatically. You still can enter a password manually if you want.

Since original UNROM cartridges have no PRG RAM memory, there are two versions of the patch:

- A patch that leaves UNROM mapper and adds NES 2.0 header with information about the presence of unusual battery-backed PRG RAM. This ROM will work on modern emulators, modern flash cartridges, self-made UNROM boards with PRG RAM, and compatible multicarts (COOLGIRL, etc.)
- MMC3 conversion. This ROM will work on all emulators, compatible MMC3 boards (TNROM with CHR RAM) and compatible multicarts (COOLBOY, COOLGIRL, etc.)

ROM information:
Database match: Metal Gear (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: 9AAA7C001465311AE79D84644AA5FCE1F9766860
File CRC32: B27DE2D8
File MD5: 347F6B957CFF910CD058D7BFD3CEE588
ROM SHA-1: 2783BEF3CC207E9BF57A65EEA5AB9B68E2214AF0
ROM CRC32: 817431EC
ROM MD5: 9CE6AF110EEAC2EB1BA8DB803D15391B

Credits:
Alexey 'Cluster' Avdykhin
clusterrr@clusterrr.com
https://clusterrr.com