Making the Brovi E3372-325 4G/LTE modem work on OpenWRT 22.03

The device seems to have some compatibility quirks concerning Linux support at least with the firmware version I received it with. An elusive update which cannot be found anywhere is claimed to resolve the issues.
For OpenWRT I eventually managed to use information from multiple sources to botch up a script that performs the necessary mode switching to get it working.

Switching Huawei E3131 Hilink to modem mode

Latest Huawei 3G/4G modems come with firmware that implements a feature Huawei calls “HiLink“, transforming the classical PPP dial-up connection to an always-on wireless broadband. This feature is highly useful on Windows operating systems, but will add an extra level of complexity to using the modem on Linux or in …

Obtaining administrator access on Huawei HG8247H

My ISP upgraded my connection from VDSL to fiber and gave me new hardware to go with it – the Huawei HG8247H GPON. However, as I am already using a fully configured DDWRT-ed router for all my networking tasks, I needed to turn the Huawei into a media converter and pass the static IP to my second router – not the easiest task as it appears.

The Huawei my ISP uses comes with manufacturer firmware and blank configuration so the default logins of still work, but as soon as its WAN gets connected it grabs the configuration from the ISP and the administrator login changes.