Most of the videos and tutorials and forum discussions are now outdated. This took many hours to discover, so I felt obliged to share here.
This is the hardware and steps to Tasmota-fy the Sonoff Touch Smart Switch, T0 (no RF), US (Canada), 3C (3 gang / 3 relay).
It’s become increasingly difficult to find smart switches that still have ESP and aren’t locked out from writing Tasmota. There is a process for the Beken SoC, but it was a bit daunting, and I already know Tasmota.
Blakadder suggests that GPIO0 is found on R19 (v1) or R18 (v2). The current boards inside the switch are v2.0.1, and GPIO0 is not found on either side of both of these Rs.
Another thread suggested using TP1, and this is the correct location to easily access GPIO0 to boot into flash mode.
My first FTDI adapter just threw errors constantly, and this held back progress, but when I swapped it out for an older FTDI dongle, success was immediate.
I simply used the web installer at https://tasmota.github.com/install
I don’t have a 3D printer, so I had to modify a 3 gang wall plate by cutting out the bits which impeded the box of the switch from passing through. Fill in the void with those blank panels.
(I may try to use two blank 1 gang well-placed and cut the edges down. I don’t love the look of the modified plate and the fillers.)
The price of the 3C is only $2 more than a 1C, so even if there is just a single light to switch in the box, it’s best to spend the $2 extra to get two more switches. (These can be disassociated from the relay, and used as a switch to do other automations.)
