Sorry for the necrothread, but something is not clear. Do headers apply to SNES roms only, or are other platforms/portables affected as well? My rom patching days are on hold until I know for certain what to deal with.
Also, can headers be added to or removed from ips patches, or does this only apply to roms? If both, which is recommended?
"Everything" has a header. Which of course doesn't mean the header in a sence of what you consider as a header for ROMs.
ROMs have headers because of the copiers. This is an additional data written at the beginning of the ROM, which is a leftover data, that the copier needed when scanning the cartridge into the file. "Such" headers are useless. These are called copier headers or external ROM headers.
Some other "types" of headers are however essential, like the header in a zip file, similar with IPS.
Simplified: IPS doesn't have the same type of header, which would be "compatible" to what we know as a ROM header, since every ROM has the "actual" or "inner" header.
No external ROM header is recomended, since they only cause trouble, when patching and when calculating pointers in hex. Also: IPS can not have an external header. But you can falsly make an IPS by comparing a headered original and unheadered hack. It is best to avoid external headers.
But since I come from the SMW community, external headers are popular, since the main editor rquires one. So if you are patching any SMW hacks, you definitely need this obsolete data, since after any SMW hack is complete, everyone tends to leave the header.
My rom patching days are on hold until I know for certain what to deal with.
Before you patch, make sure you check the "Rom/Iso info". You have the CRC of the file to patch to there. It has to match with the CRC of your original ROM. At "patching info" check if it says header or no header. This should clear things up.
Another problem however is, if authors included the header in the CRC calculation or not. (Or in other words: if only these annoing headers wouldn't exist).