Remove header

Most MSU-1 hacks are for non-header roms. Here's a short tutorial what a header is and how to remove it.

Usually if your rom has a smc extension it has a header and sfc extension has none. This however isn't always the case. To verify open your rom in a hex editor like HxD:
https://www.smwcentral.net/?p=section&a=details&id=4625

If your rom has a header, you notice it that the first $200 bytes are almost completely zero:s:


Example of a header (marked in blue)

To get rid of it, download the following tool (snes rom utility):
https://www.romhacking.net/utilities/593/

Start it, open the rom
if the rom has a header click on the right side below tasks -> remove header, ok
the program automatically creates "romname_noheader.smc"
Now you simply need to patch this rom with the msu patch and rename it.

For *NIX users, you don't need any tools not available already.

Hexdump

Hexdumping the beginning could be done with xxd or hexdump which is available by default on most systems, e.g.

Code:

xxd -l 1024 rom.smc

Strip header

Stripping the first 512 bytes is as easy as

Code:

dd bs=1 skip=512 if=rom.smc of=rom_noheader.smc

or

Code:

tail -c +513 rom.smc > rom_noheader.smc

Add header

To add a header of zeroes to the file you could do something like

Code:

cat <(dd if=/dev/zero bs=1 count=512) rom_noheader.smc > rom.smc

or if your shell doesn't support that kind of in place file descriptors

Code:

dd if=/dev/zero bs=1 count=512 | cat - rom_noheader.smc > rom.smc

Misc

If you for some reason would need it you could also had backed up the existing header, say with

Code:

dd if=rom.smc bs=1 count=512 of=header.bak

and added it back later with

Code:

cat header.bak rom_noheader.smc > rom.smc

Gotta love good old command line tools.