There is support for DD-WRT for DIR-890L. I decided to flash to DD-WRT for 890L to work Singnet Fibre. These were the recommended VLAN settings. Cool. 890L managed to get IP address from Singnet.

Find the webflash interface via the stock firmware and point it to the 'factory-to-ddwrt.bin' file, flash and reboot again. If it reboots to DD-WRT, great, if not, reboot again, just to … Remove / uninstall DD-WRT or 3rd-party firmware and revert May 13, 2014 #6492 (r37837 - Archer C7 V5 return "Invalid file type") – DD-WRT Rename the factory-to-ddwrt file to this filename and reboot the router. The router will grab the file and flash it. Wait ~10 min before rebooting the router. It

How to reset TP-Link router to factory defaults | TP-Link

Restore TP-LINK Archer C7 DD-WRT to Stock - YouTube Jan 23, 2017 Upgrading D-Link DIR-615 Router to DD-WRT – jeedo.net

Currently on Firmware v1.0.3.187766 and have downloaded factory-to-ddwrt.bin for the correct model (WRT1900AC S). Go into the router - connectivity - (check for updates is OFF) - choose file - start. Blue line runs across screen in long and short jumps and unit eventually reboots and says the update is successful.

DD-WRT Kong Mod for NETGEAR R7800 (Factory to DD-WRT Dec 12, 2016 Factory Defaults - DD-WRT Wiki NVRAM Merge needed with Hardware#NVRAM.. Every router has a memory chip inside that stores persistent settings between reboots. The NVRAM is also retained between flashes of different firmware versions or even different firmware versions! DD-WRT for R7500/R7500v2 | MyOpenRouter Flash R7800-factory-to-ddwrt.img build from Netgear firmware. Once dd-wrt is running you have to use ddwrt-netgear-R7800.bin to flash future updates. Currently known issue:-2G and 5G leds are not operational since they cannot be controlled through gpio. Current opensource wireless driver has no support to control these leds.