How to change bootrom on ems 64 smart cart

The Bootrom is hard coded into the gameboy itself and actually acts as a data check to ensure proper communication before booting any software. It cannot be changed. If you don't want to see the Nintendo logo, you may swap your CPU for a Super Gameboy CPU.

Its tough work;
http://noizeinabox.blogspot.com/2012/06 … plant.html

Indeed it can, some retro pirate carts did this (eg Sachen carts?)  and quite a few other people have done it before.

A quote from RivalCorp (AKA Kevan Killion) from this video showing the work he did surrounding custom logos.

https://www.youtube.com/watch?v=rtNZGbpxl8k

"Added some logic to display a custom boot logo on the Gameboy and still launch the game. When the Gameboy boots up it loads in the data from 0x104-0x133 in the ROM header. It then scrolls that image to the middle of the screen. It once again reads the data from 0x104-0x133 and compares it to the data stored internally in the Gameboy. If any of the data is different on the second time it reads it compared to the data stored internally it will fail to boot the game.

What I did was once the Gameboy starts it reroutes the data from Flash to a data stored on the FPGA containing the custom logo. Once it is done reading the data the first time it changes back the addressing to read from the Flash that contains the ROM. To sum it up shortly it Reads custom data then reads the real data the second time."

He did it using an FGPA but there have been others to do so without.

Last edited by DaRkO (Oct 4, 2013 8:45 am)