E5372 21.290.23.00.00 webui 17.100.19.01.00 mod v1.5.2

Custom 21.290.23.00.00 firmware and 17.100.19.01.00 web interface for E5372

The firmware is based on the original global firmware version 21.290.23.00.00. It can be installed on any previous firmware (unless you have locked bootloader), or updated from a modified firmware.
Flash through balongflash: Windows, Linux.

Changelog v1.5.2 (04.02.2020):

• Fix for OpenVPN: Add missing symlink at bin/openvpn_scripts/ip
• Make symlinks to toolbox and btools to save space on /system partition
• Update oled_hijack.so with LD_PRELOAD unsetenv version (fix for DNS over TLS on-screen menu)
• Update adblock list
• Trigger OpenVPN reconnection if OpenVPN is running by default

Attention!

This firmware can render your device unbootable! Use it only if you are aware of all the risks and consequences. In case of any problems, do not wait for help, you're on your own. Do not install firmware by non-tech-savvy people request, and do not sell routers with this firmware preinstalled.

Why does the router show "Not for resale, faggot!" text when turned on?

It is assumed that the firmware to be installed by tech-savvy people which would read its description to be aware of the risks associated with it, and would be able to modify the FW to their own needs, fix small bugs or at least update or revert to stock.
This firmware is mostly not for ordinary users, but for me and Huawei devices researchers.
The text "not for resale, fag!" was made in order to make selling the router with this firmware uncomfortable and embarrassing process. I do not want uninformed customers to receive a device with disabled security subsystems and no updates from the manufacturer.
Many may simply ignore "not for resale" phrase, but the expletive word makes you think it over and ask additional questions to the seller.