To download Shelly firmware see this guide
Technically they could role out an update bringing in matter with verified/secure boot locking the device down completely. Taking away ownership and the right/possibility to repair or extend functionality. On the other hand Schneider even could introduce subscriptions for formerly free (local) features to boost revenues. It will not be the first nor the last time a company did a move like that. Business as usual. 
Isn’t Secure Boot only a thing on S3 and P4 boards? And couldn’t you just attach a serial converter to flash?
They already own the Clipsal Wiser zigbee (and matter) range. Pretty good, expensive though.
No, secure boot doesn’t allow that. 
No, even 10 year old esp32 support that.
In short: You can’t own matter devices, they own you!
I saw this the other day on Facebook: A message from Dimitar Dmitrov.
For those that cannot or don’t want to access FB (completely understandable):
A person not in charge any more gives an AI slop statement about the company he sold - futurehome vibes 
Also the thing which is not written (like a “per contract total business independence for x years after acquisition”) does tell that such a clause probably doesn’t apply or exist. Beside Schneider for sure wouldn’t accept such terms for an acquisition 
This thread has been a real rollercoaster. First an earthquake, then high hopes, and finally - a straight road to hell! I own about 20 Shelly devices, the largest number of products I have from a single brand. 2 more years isn’t that bad, I’ll hold onto good memories.
Shelly will probably go down a rather “pleasant” enshitification compared to many other brands. At this very moment you might still hold power over your device and with many (ESP based) shelly devices you can overwrite the original firmware with some custom ESPHome (or other goodness) instead. If that’s done Shelly/Schneider lost all access to their your device. Congrats, you now own your sh.. 
Make them permanent 
Long ago, (in IoT timespans) I got severely burned by a cloud based application. Never again. Then Insteon imploded just about the time I was getting fed up with their cost … a light switch that costs as much as a cheap computer? Realy?
Thus I designed my Universal Light Switch (ULS) (link is to prototype). The hardware is simple and inexpensive, it’s only requirement is an MQTT broker, though if you want to connect disparate devices, it connects to HA.
My point for this thread: the only way we can stem the tide of this enshittification is to create and support alternatives. (by support I mean spending time improving alternatives.)
Dang, I was not aware of that. I always thought Secure Boot on ESP32s was mostly a joke…
Well, that makes me nervous. I will probably look into reflashing mine with ESPHome when I get some free time.
EDIT: mine are running too new of a FW for Tasmota. Hmmm
UPDATE:
Guys, I got ESPHome OTA updated onto my Shelly Plus Plug US, FW 1.7.5 without any need for Tasmota.
I used GPT-6 Sol to inspect the stock FW mappings using Ghidra, then it seemingly injected the ESPHome app into Shelly’s partition mapping app0, and then ESPHome booted up just fine using Shelly’s custom ESP-IDF 5.4.1-s4.
After that, ESPHome’s OTA bootloader update works and I now have a fully unlocked Shelly running ESP-IDF 5.5.5.
I am still figuring out mappings for the hardware but we are getting there, and I will make a post on how to do it once I get it verified on my other Plug USes.
Thanks, I’m glad that option exists. Honestly, I’m a slow updater, still using Shelly fw. version 1.7, while the latest is 2.X. My devices are local, they don’t auto-update, and they work flawlessly, so for now, I don’t feel the need to change the fw. I could do that two years from now, for all it matters 
Same here. I’m running v1.7 as well. I haven’t had a need to upgrade the firmware when running local with home assistant.
Got a 1.27mm pitch header to be fancy, made it ugly, used the wrong ESPHome config then finally have ESPHome working on one of my Shelly Plus 1PMs.
I just used Kagi and ESPHome via Home Assistant, a random github gist and now, most importantly, I can calibrate the Shelly Plus 1PM. I’ll be moving as many of my Shellies to ESPHome or Tasmota as I can this weekend. I got 6 in 2021 and their mismatched readings made me put them in a drawer until my Gen1’s started to fail last year.
They have the single core ESP32 chip, even though the PCB says 0.2.0 which seems to suggest dual core, but they are from 2021 so the dual core firmware booted, complained about having only one core, then crashed. The single core booted, but then reset due to a brown-out-detection error, which is fine and goes away on 24VDC or proper AC. Now I even get a relay voltage reading, which is not useful but it is interesting.
I can’t find documentation for this, but if you connect DTR to esp32.GPIO0 and RTS to esp32.RESET/EN/CHIP_PU you don’t need to lift a finger. Sadly no mgos-to-tasmota OTA path from this now-unsupported version 1.7.5 firmware from Shelly.
Not sure what I’m going to do with my Gen3 Duo bulbs yet, maybe just block their internet and move on. No internet means no firmware upgrade temptation.
My opinion piece on this: I don’t like the change, but I don’t blame them. Once a statement like this is out with that amount of money there’s no way out if, more so if you are publicly traded. If they said no and did some moral grandstanding about staying rooted in the DIY world (I would want them to, but the roots got real thin with their ESP32 range), I would think “good on 'em” and not change my attitude toward the brand very much. If they say yes, I go for an emotional roller coaster that doesn’t matter to anyone and eventually get back to my workbench to learn some basic stuff. If I was the founder, I don’t think my passion and ideologies would be strong enough to turn away such a deal. I’d like to imagine that I would throw the old firmware out of the deal as accidentally open-sourced though, especially those pesky STM32 chippies.
I want to buy the cleanly pre-built and nicely packaged thing from someone I can point at if it burns my house down, but I want full control of it’s software. That makes no sense for brand and safety reputation of the seller, but I’m not the seller.
i have cracked one open (Duo bulbs), when i have some time, i will do the pinout.
no OTA ;( but maybe there is a way to open them, without cracking it.
I got my Gen2 Plus Plugs flashed seamlessly OTA with ESPHome.
I created a thread and repo for instructions. I’m sure the same principle could be applied to OTA other Shelly devices 