Method downloadToFlash

tools/xsbug/esptool.js:741–799

(data, offset, compress = false, progress)

		this.#baud = baud;
	}
	async downloadToFlash(data, offset, compress = false, progress) {
		const uncompressedByteLength = data.byteLength;
		const FLASH_WRITE_SIZE = 16 * 1024;

		if (compress && globalThis.pako) {
			data = pako.deflate(data, {level: 9});
			console.log(`Compressed image from ${uncompressedByteLength} to ${data.byteLength} bytes.`);
		}

		const cmdOffset = (compress && globalThis.pako) ? (Bootloader.FLASH_DEFL_BEGIN - Bootloader.FLASH_BEGIN) : 0;

		let blocks = Math.ceil(data.byteLength / FLASH_WRITE_SIZE);
		const total = blocks;

		let payload = new DataView(new ArrayBuffer(4 * 4));
		payload.setUint32(0, uncompressedByteLength, true);		// little-endian
		payload.setUint32(4, blocks, true);						// little-endian
		payload.setUint32(8, FLASH_WRITE_SIZE, true);			// little-endian
		payload.setUint32(12, offset, true);					// little-endian
		await this.command(Bootloader.FLASH_BEGIN + cmdOffset, payload.buffer);
		let reply = this.parseReply(await this.getReply(), Bootloader.FLASH_BEGIN + cmdOffset);

		let block = 0;
		while (blocks--) {
			const fragment = data.slice(block * FLASH_WRITE_SIZE, (block + 1) * FLASH_WRITE_SIZE);
			payload = new DataView(new ArrayBuffer((4 * 4) + FLASH_WRITE_SIZE));
			payload.setUint32(0, FLASH_WRITE_SIZE, true);	// little-endian
			payload.setUint32(4, block, true);				// little-endian
			payload.setUint32(8, 0, true);					// little-endian
			payload.setUint32(12, 0, true);					// little-endian

			if (0 === blocks) {		// last block
				if (0 === cmdOffset) {
					payload = new Uint8Array(payload.buffer);
					payload.fill(0xFF, 16, 16 + FLASH_WRITE_SIZE);	// pad uncompressed
				}
				else {
					const byteLength = data.byteLength - (block * FLASH_WRITE_SIZE);
					payload.setUint32(0, byteLength, true);
					payload = new Uint8Array(payload.buffer.slice(0, 16 + byteLength));	// shrink compressed
				}
			}
			else
				payload = new Uint8Array(payload.buffer);
			payload.set(fragment, 16);
			const checksum = this.espChecksum(payload, 16, payload.byteLength);
			await this.command(Bootloader.FLASH_DATA + cmdOffset, payload, checksum);
			reply = this.parseReply(await this.getReply(Math.floor(1000 + (payload.length / (this.#baud / 10) * 1000))), Bootloader.FLASH_DATA + cmdOffset);
			block += 1;
			progress(block / total);
		}

		payload = new DataView(new ArrayBuffer(1 * 4));
		payload.setUint32(0, 1, true);		// little-endian (STAY IN LOADER - DO NOT REBOOT)

		await this.command(Bootloader.FLASH_END + cmdOffset, new Uint8Array(payload.buffer));
		reply = await this.getReply(2000);
		reply = this.parseReply(reply, Bootloader.FLASH_END + cmdOffset);