Dear Iasutsatu,
Please check the Following link, you need to install the USB driver in your Windows PC firstly, then unzip Qflash package, connect to USB DM port, unzip EC20 firmware package, choose any file in firmware package, then click start button, it will upgrade the firmware automatically, you just need to waiting for the upgrade successful. Thanks!
By the way, could you share your company information with me, as we know EC20_GW module is just used for state grid customer, and other customer should not use such module. Please note. And about UC15 module, please check your current firmware with ATI first. Thanks!
Windows USB driver:
https://cnquectel-my.sharepoint.com/:u:/g/personal/asean-fae_quectel_com/EbmCGzd2gAtBo_OZrTOYV3kBL5JD7_TvQmmTASwIi7SIPg?e=qcIJwX
Upgrade tool: QFlash
https://cnquectel-my.sharepoint.com/:u:/g/personal/asean-fae_quectel_com/EWjAQFUUuoFEvKld6L9q2vMB-whsRb1hPb_Y7gu3Gn8lqw?e=5SeedU
EC20CEFBKR03A09M2G_GW:
https://cnquectel-my.sharepoint.com/:u:/g/personal/asean-fae_quectel_com/EZE5nZ2lZdhAiMOejYJ9pgwB7N-G6W7nVrQtRm6ls_TOnQ?e=EuEvY6