private void writeHexString(String hexString, int offset) {
		if (hexString.length() % 2 != 0) {
			return; // error
		}
		for (int i = 0; i < hexString.length() / 2; i++) {
			rom[offset + i] = (byte) Integer.parseInt(
					hexString.substring(i * 2, i * 2 + 2), 16);
		}
	}