The most reliable way to enter download mode is to send the command. You can do this using a terminal program like DC‑Unlocker:
Unauthorized modification of device software typically voids the manufacturer's warranty. Additionally, the legality of network unlocking varies by jurisdiction and the terms of service agreed upon with the service provider. ZONG E5573CS-322 21.323.01.00.306 DIRECT FLASH.7z
Reinsert the battery. Hold down the and WPS buttons simultaneously while connecting the micro-USB cable to your PC. The most reliable way to enter download mode
The COM port is being utilized by another background process. ZONG E5573CS-322 21.323.01.00.306 DIRECT FLASH.7z
Before attempting to modify the router firmware, certain hardware and software components must be assembled on a Windows computer: