From this post, you can download much firmware of the Huawei E5730 router (gateway). Almost all the firmware is paid worldwide, but only I offer these for free. If any firmware is missing in the post, let me know; it will be updated via comment.
Download Firmware Huawei E5730s-6 Update 21.146.99.07.00 (Universal)
Download Firmware Huawei E5730s-6 Update 21.146.11.00.00 (Universal)
Download Firmware Huawei E5730s-6 Update 21.146.13.00.00 (Universal)
Download Firmware Huawei E5730s-2 Update 21.143.27.02.1217
Download Firmware Huawei E5730s-2 Update 21.143.27.00.234 (MTN Iran)
Download Huawei E5730 Update WEBUI 17.100.09.03.03 NE5 (Universal)
Download Firmware Huawei E5730s-2 Update 21.143.27.00.1262 (Malaysia)
Download Firmware Huawei E5730s-2 Update 21.143.27.00.1080 (Hong Kong)
Download Firmware Huawei E5730s-2 Update 21.143.25.01.1133 (Saudi Arabia Open Market)
Download Firmware Huawei E5730s-2 Update 21.143.27.00.1218 (Finland)
Download Firmware Huawei E5730s-2 Update 21.143.27.00.1240
Download Huawei E5730s-2 Update 21.143.25.00.00 Universal
Download Firmware Huawei E5730 Update 21.143.25.01.158 (Globe Philippines)
Download Firmware Huawei E5730s-2 Update 21.143.27.00.1021
Download Firmware Huawei E5730s-2 Update 21.143.27.00.00 Universal
Download Firmware Huawei E5730s-2 Update 21.143.25.00.778 (Russia Open Market)