[RTL8710CF] How to Reflash Firmware on Kasa HS200 WiFi Smart Switch (US)

Kasa Smart Single Pole Light Switch by TP-Link (HS200)

The case is a bit difficult to crack open, but it's possible by using only a flat head screwdriver and by prying the sides. Here's the PCB on both sides:





I connected the 5V pad on the PCB to the 5V rail of the USB Serial Converter. The rest of the pads are clearly labeled in the pictures. It's like it was meant to be reflashed

Short the GPIO0 pad to the 3V3 pad next to it to enable bootloader mode. Use the "Restart" tact switch to restart the MCU. The "Reset" tact switch is just another input.

The rest is easy! Follow this guide to flash the firmware: https://www.elektroda.com/rtvforum/topic4097185.html

Here's a partial template I've come up with. It allows control of the relay and the main LED by the main switch. The "Reset" switch and the tri-color "wifi" LED are mapped but I'm not sure what to do with them. I'd like to use them for their original intended purpose but I don't know how. I hope that helps

thank you for the template and the firmware backup you sent. I've not been able to get it into a pairable state to determine much from it at this point.

Jerther wrote:

the tri-color "wifi" LED are mapped but I'm not sure what to do with them. I'd like to use them for their original intended purpose but I don't know how.

There are "LED_WIFI" and "LED_WIFI_n" to use the WiFi LED. Will they do what you want?

max4elektroda wrote:

Jerther wrote:

the tri-color "wifi" LED is mapped but I'm not sure what to do with them. I'd like to use them for their original intended purpose but I don't know how.

There are "LED_WIFI" and "LED_WIFI_n" to use the WiFi LED. Will they do what you want?

I just found the documentation for pin roles. I'll do some tests.

https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/ioRoles.md

Added after 7 [hours] 1 [minutes]:

I have fiddled a bit with the LED_WIFI roles and the best I could come up with is to use the green led, and it follows the behavior described in the documentation but that's quite a bit far from the original:

Blinking Amber and Green: App-Config mode initiated.
Green: Lit up for about 30 seconds when successfully connected to the Wi-Fi network, then turns off.
Blinking Amber: Resetting.
Red: No Wi-Fi connection.

Now it's ok if the behaviors are different, but the led staying lit is a bit annoying, and I'd like to make use of the red and amber colors too if that's possible.

The led works by combining P7 and P9:
P7 only = green
P9 only = red
P7+P9 = amber

Any ideas?

did you get any further since you last posted? I forgot about this thread and have not yet posted added your template

Added after 20 [minutes]:

info from dump

I haven't. My last post is as far as I went.

how would you like the LEDs to behave?

Flashing amber for wifi connecting? (not even sure you can assign two wifi_led roles and they function together without some autoexec script)
then green for socket on and red for socket off?

Added after 11 [minutes]:

I've assigned a two-LED plug I have both WifiLed and they behave as one - purple wifi connecting indicator in my case - red/blue

It would be nice if the wifi LEDs behaved like the original and used the full three colors. If it is not possible, then at least have the green led turn off after some time when wifi is connected. Right now it is always lit and it's a bit annoying because of the way the switch was designed.

Here's what the switch looks like when it's on with my current template. The white circle is on when the switch is on, and it is off when the switch is off. The green wifi LED is always lit.

I guess it'd be something to script, change the role of each pin depending on the state of the wifi (or other state/trigger). Here's a basic example that could be built upon

https://www.elektroda.com/rtvforum/topic4012418.html#20804036

Added after 18 [minutes]:

https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/autoexecExamples.md

https://github.com/openshwprojects/OpenBK7231T_App/blob/main/docs/commands-extended.md

Added after 1 [minutes]:

https://youtu.be/kXi8S12tmC8?si=0ni9o9E2WePYspU_

I haven't had time to play with scripts yet, but I've had a wifi outage yesterday. Of course the wifi led on the switch started to blink red-green in alternance, which is expected. But once the wifi came back up, the switch did not reconnect automatically. The wifi led kept on blinking for hours, until I hit the small "restart" button on the switch. Then it reconnected fine.

It's like the microcontroller gives up reconnecting at some point, and I believe it's not intended, because other IoT devices I've reflashed with openbk reconnected without my intervention.

ah interesting. That's a bit of a show-stopper for RTL87X0C devices running OpenRTL.

I think @max4elektroda did some stuff on several platforms regarding wifi reconnection behaviour, but maybe that was (just?) SSID2 support.

Added after 3 [minutes]:

and maybe @insmod who ported RTL

I don't have a RTL87X0C device, but i have RTL8710B and RTL8720D devices running, and they all share wifi code.
What version are you using? I improved wifi code some, previously it could've crashed the device. Also, in recent update i turned on realtek own auto reconnect feature, in addition to openbeken one.
I don't have problems with wifi anymore, and my RTL8710B plug uptime is at about a month, with wifi outages.
This particular plug is pretty unstable with wifi when there's any load. I've had 1.5 hours today of when the plug disconnected and didn't reconnect, but it eventually did.
You could also try to enable flag 51, but i doubt that it would change anything.

divadiow wrote:

I think @max4elektroda did some stuff on several platforms regarding wifi reconnection behaviour, but maybe that was (just?) SSID2 support.

Yes, some SSID2 stuff and a faster try for reconnect during the first seconds after startup.
All the WiFi code is usually in a library blob from the manufacturer, I expect the same here.
If you don't have a serial connection to see logs during this time it will be hard to figure out. Maybe SSID is not found, authentication failed...

The version I'm using is the one introducing support for RTL8710C. I understand there's been multiple improvements since, so I'll update the firmware and check if I can make the switch fail to reconnect again.

Meanwhile, what needs to be done about the template so it makes the official list?

Jerther wrote:

Meanwhile, what needs to be done about the template so it makes the official list?

https://github.com/OpenBekenIOT/webapp/commit/177358499fbb3ac27904e756d9de8ceaedfe4b2f

No way! :D

So it looks like I'm golden then! Nice! I will report back if I find anything about the WiFi.

well, that PR's been open a month, I think @p.kaczmarek2 has been busy

There are no pending Web App pull requests?

oh dear. my bad 😳

would help if I had opened one

1.18.12

"Sorry, OTA update not implemented for OpenRTL87X0C"

Oh no so I have to remove the switch from the wall and reflash the firmware the hard way...

Is OTA implemented in later versions, so I don't have to do that again?

>>21528804
OTA was implemented even before the release, so don't worry.

Jerther wrote:

Sorry, OTA update not implemented for OpenRTL87X0C

I don't recall if the "new" OTA on the Configure menu was present in that version, maybe it wasn't. If that's the problem you should be able to do OTA from the Web App.

Added after 20 [minutes]:

Just checked the code, that should be the case, this new approach for OTA was implemented while @insmod was doing the heavy lifting with OpenRTL so it's not present in 1.18.12 yet.
But Web Application OTA should work

Ok there's an OTA menu in the web app. Phew! 😅

I went ahead and ordered about a dozen of these switches and while the MCU is the same, the board layout is different. Shouldn't be a problem since all test points are still accessible. I'll post pictures and more details when I can.

The reset button wasn't doing anything. I made a PR to use it to trigger safe mode.

https://github.com/OpenBekenIOT/webapp/pull/191

Thank you, merged. Let me know if you have any futher ideas for improvements.