Method read

SerialFlash.h:85–93

		return false;
	}
	uint32_t read(void *buf, uint32_t rdlen) {
		if (offset + rdlen > length) {
			if (offset >= length) return 0;
			rdlen = length - offset;
		}
		SerialFlash.read(address + offset, buf, rdlen);
		offset += rdlen;
		return rdlen;
	}
	uint32_t write(const void *buf, uint32_t wrlen) {
		if (offset + wrlen > length) {
			if (offset >= length) return 0;