SpeedTouch 780 - Firmware Upgrade

Ok, so Google is completely unhelpful for this. I ended up finding the German SpeedTouch forum, which has a pretty complete list of firmwares.

Lessons learned: SpeedTouch 780WL is NOT SpeedTouch 780 DXT. If you have a firmware that says 7.4.4.7 or similar, DO NOT USE IT. It will not brick your router, but you will have to use the Bootp method to downgrade the firmware to a compatible version, because otherwise it will stay stuck at the factory settings with no chance of letting you log in.

If you did make the mistake of installing the wrong firmware, don't panic! What you will need to do to fix it is the following:
* Get the firmware upgrader (you probably already have it, since you installed the wrong firmware).
* Get the correct firmware! For my router it was ST780_SIP_62T2_bant-r.zip because it has a BANT-R board.
* Unzip it, keep it at a handy location.
Shut off the power to the router. With a pen or toothpick, push down the wee little reset button on the right side of the back panel (near the VoIP ports), keep it pressed, and at the same time turn on the power again. Hold the reset button until the front LEDs change from one red to one green and a flashing orange (some models may have alternating red/green flashing LEDs. Either way, you should be able to notice when the change happend).
* Start the firmware upgrader. It will scan your network for the router. If it doesn't detect it, close the upgrader, and restart it. I had to try several times before it worked for me.
* Select the appropriate firmware. You may have to check a box acknowledging that you are downgrading the firmware before you can hit next. Do the upgrade.
* If it fails, run it again. The process seems to have a tendency to break if you as much as breathe on the router, so 2-3 tries may be necessary. Don't give up too quickly.
* Once it finished upgrading, the router will be set to factory defaults. Go to the setup page, configure everything, and off you go.

Note to self: For future upgrades, the settings are VPI 0.35, PPPoE, user@host / pass.