C. Serial console + TFTP (robust)
If your ISP has "crippled" the device, you can sometimes flash an generic Huawei or O2 firmware to unlock all menu options . Modem Configuration Guide HG658 - TPG huawei hg658 v2 custom firmware
The scene is niche but alive. OpenWrt offers a second life to this outdated ISP router, transforming it into a flexible, open-source gateway. The trade-off is losing the DSL port and needing technical skill to flash via serial console. transforming it into a flexible
Connect JTAG pins, use flash programmer to write bootloader and firmware images. huawei hg658 v2 custom firmware
: The OpenWrt Table of Hardware lists the earlier HG658b/c as having limited support, but the HG658 V2 does not have an official OpenWrt or DD-WRT release.