Hola.
Código PHP:
void replaceByte(const AnsiString &aFilename, const unsigned char &Byte,
const unsigned int &position)
{
TFileStream *stream;
stream = new TFileStream(aFilename, fmOpenWrite);
try
{
stream->Seek(position, soBeginning);
stream->Write(&Byte, sizeof(Byte));
}
__finally
{
delete stream;
}
}
Saludos