The update reset the Wi-Fi channel to a country-specific band (e.g., Channel 13 which your laptop doesn't support). Fix: Hard reset the device: Remove battery, wait 30 seconds, reinsert battery. Press and hold the reset button (next to the USB port) for 10 seconds using a paperclip. Then reconfigure Wi-Fi SSID and password.
Is your router (like Airtel, Vodafone, MTS) or is it generic? Update Software in HUAWEI E5573CS-323
: Open a web browser and enter the IP address found on the sticker under the battery (usually 192.168.8.1 The update reset the Wi-Fi channel to a