[BK7231T] My HTTP server, configurator, MQTT support from Home Assistant

p.kaczmarek2 205803 1308

TL;DR

OpenBK7231T adds a cross-platform C HTTP mini-server, web pin configurator, and MQTT integration for BK7231T-based WB2S/WB3S modules with Home Assistant control.
The design splits Windows-specific networking from reusable HTTP and pin code, so the same configurator and packet parser can run on Windows and on the BK7231T firmware.
The server listens on port 80, uses one int as a channel bitmask, and therefore supports up to 32 channels on a 32-bit platform.
MQTT callbacks propagate relay/button changes to Home Assistant and accept commands back, and a 4-relay setup uses wildcard topics like wb2s/1/get through wb2s/4/set.
The current pin configurator does not save settings to Flash yet, so configuration is still coded and compiled into the firmware.

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#1291 21787297 22 Dec 2025 10:08

divadiow divadiow

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Post #1291
21787297 22 Dec 2025 10:08

Negative. My tests were not with Easy Flasher because I know the T protection gets in the way.

Besides, this wouldn't have made sense if I was:

divadiow wrote:
I am seeing switches between BK7231S_1.0.5 and BK7231S_1.0.6 BL
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#1292 21787326 22 Dec 2025 10:36

p.kaczmarek2 p.kaczmarek2

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Post #1292
21787326 22 Dec 2025 10:36

Interesting, so you probably flashed the new bootloader correctly and the issue arise only if overwrite it with non functional data.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#1293 21787335 22 Dec 2025 10:41

divadiow divadiow

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Post #1293
21787335 22 Dec 2025 10:41

Well indeed! I've flashed loads from 0x0 now. Very interesting.
#1294 21796922 02 Jan 2026 23:33

divadiow divadiow

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Post #1294
21796922 02 Jan 2026 23:33

divadiow wrote:
and I guess all the new variants need catering for too or users will OTA to default release?

just playing with this https://github.com/OpenBekenIOT/webapp/compare/main...divadiow:OpenBekenIOT-webapp:hlwota

the intention being that OTA now prefers Open<chip>_<ver>_<variant>.rbl (chip + variant) based on the device’s build suffix, and falls back to Open<chip>_<ver>.rbl (generic) if no variant asset exists.

seems OK so far, but needs more testing.

let's you go from generic to variant at the moment

currently with hard-block if choosing different variant

doesn't cater for the _ALT variants though as they're not as <buildver>_ALT in /api/info

Added after 51 [minutes]:

ESP+BL602 ota extension for variants https://github.com/divadiow/OpenBekenIOT-webapp/commits/hlwota/

should I pursue this or is the code rubbish?

Added after 1 [hours] 1 [minutes]:

latest commit doesn't allow any variant cross-flashing. legacy wrong chipset "invalid ota file was selected" warning remains intact
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#1295 21797174 03 Jan 2026 09:15

max4elektroda max4elektroda

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Post #1295
21797174 03 Jan 2026 09:15

divadiow wrote:
latest commit doesn't allow any variant cross-flashing

Personally I think this is too much. I think a warning would be fine, or a switch "allow change in variants".
Just imagine I realize I used the wrong variant or added a new sensor and can't change to the needed file.

Just as a possible extension, no idea if/how to realize (but my PR to include the defines in a build might be a start): The top version would be to extract the drivers per variant so the user can see/decide if the variant fits the requirements.
#1296 21797177 03 Jan 2026 10:21

divadiow divadiow

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Post #1296
21797177 03 Jan 2026 10:21

max4elektroda wrote:
Personally I think this is too much. I think a warning would be fine, or a switch "allow change in variants".
Just imagine I realize I used the wrong variant or added a new sensor and can't change to the needed file.

I agree. I had imagined directing people to the other OTA option in main gui, but why make it unnecessarily hard. A warning note would be enough

Added after 1 [hours] 2 [minutes]:

Relaxed.

Warning generic->variant

Warning variant->generic

warning variant->variant

block still for wrong platform
#1297 21797229 03 Jan 2026 10:31

max4elektroda max4elektroda

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Post #1297
21797229 03 Jan 2026 10:31

Thanks, this change really improves the usage in a very helpful way!
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#1298 21797300 03 Jan 2026 14:47

divadiow divadiow

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Post #1298
21797300 03 Jan 2026 14:47

cool. the variant OTA thing has been on my mind for a while + ESPs were not listed at all. I just hope the code is OK. I'll review code comments and do more testing/checking.

Added after 1 [hours] 4 [minutes]:

it seems LN882H only matches on file extension so will look to add filename pattern check too

Added after 2 [hours] 1 [minutes]:

LN882H
wrong chipset

LN non-OTA

correct LN OTA

BL602
variant listing + accept variant OTA

warn on variant to generic

generic listing + warn on generic to variant

warn on variant to variant (future-proofing)

no warning on same to same generic

BK7238
variant listing + accept variant OTA

warn on variant to generic

generic listing + warn on generic to variant

no warning on same to same generic

wrong chipset

BK7231N
variant listing + accept variant OTA

warn on variant to variant

warn on variant to generic

generic listing + warn on generic to variant

no warning on same to same generic

wrong chipset

PR if this looks OK: https://github.com/OpenBekenIOT/webapp/pull/248
#1299 21802662 08 Jan 2026 11:34

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #1299
21802662 08 Jan 2026 11:34

The NOTE (warning) should be orange, not red, red is same as error. OBK is very user friendly and we should try our best to maintain it, so all error messages are clean and readable.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#1300 21802664 08 Jan 2026 13:06

divadiow divadiow

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Post #1300
21802664 08 Jan 2026 13:06

ok will change

Added after 1 [hours] 29 [minutes]:

slightly fancier warning style or just an amber version of the red invalid? https://github.com/OpenBekenIOT/webapp/commit/05f3b62af11dcb418742a1525a5041217a49a17d

shall I make the red invalid match? nicer?
#1301 21802788 08 Jan 2026 13:41

p.kaczmarek2 p.kaczmarek2

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Post #1301
21802788 08 Jan 2026 13:41

Even better than before, merged. Any other easy improvements at hand?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#1302 21802803 08 Jan 2026 14:06

divadiow divadiow

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Post #1302
21802803 08 Jan 2026 14:06

yay cool, thanks! Hope I didn't miss anything major.

"invalid" class style wasn't committed

https://github.com/OpenBekenIOT/webapp/pull/252

note showing on live device now

Added after 33 [seconds]:

p.kaczmarek2 wrote:
Any other easy improvements at hand?

not thought of any yet, but probably

Added after 12 [minutes]:

now showing ESP32 OTA variants available
#1303 21802821 08 Jan 2026 14:11

p.kaczmarek2 p.kaczmarek2

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Post #1303
21802821 08 Jan 2026 14:11

Can you help me test and review this by @max4elektroda https://github.com/OpenBekenIOT/webapp/pull/225?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#1304 21802826 08 Jan 2026 14:20

divadiow divadiow

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Post #1304
21802826 08 Jan 2026 14:20

sure. can do later today. I need to review it..
#1305 21802869 08 Jan 2026 14:54

insmod insmod

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Post #1305
21802869 08 Jan 2026 14:54

In ALT builds, _ALT is appended to version since 1.18.235
#1306 21802968 08 Jan 2026 17:01

divadiow divadiow

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Post #1306
21802968 08 Jan 2026 17:01

ah OK.

It was only matching on <version>_<variant>.rbl but the _ALT rbls are eg OpenBK7231T_ALT_1.18.244.rbl whereas actual variants are eg OpenBK7231N_1.18.244_hlw8112.rbl

with https://github.com/OpenBekenIOT/webapp/commit/9c923cc14550d472a5c21b70acb7043dbd671ff9

_ALT to ...

non _ALT to ...

Added after 1 [minutes]:

this does treat _ALT as a variant though rather than a generic/base release in its own right

Added after 11 [minutes]:

is const preferred over let to keep same as others?

https://github.com/OpenBekenIOT/webapp/commit/08f8a52f2d3618b2a27c973b242b984d9d6dc8ad
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#1307 21803000 08 Jan 2026 17:21

p.kaczmarek2 p.kaczmarek2

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Post #1307
21803000 08 Jan 2026 17:21

"const" means that you won't change variable later, so it's usually preferred, unless you are reassigning value to that variable, then you use "let". Still, I don't really follow this myself, it is just improving readability of the code. Also, if you declare as const, but later try to reassign the value, it will show error in console.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#1308 21803307 08 Jan 2026 22:53

divadiow divadiow

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Post #1308
21803307 08 Jan 2026 22:53

p.kaczmarek2 wrote:
Can you help me test and review this by @max4elektroda https://github.com/OpenBekenIOT/webapp/pull/225?

cool. it found some stuff in the range I gave it

the gateway addresses returned aren't right though, which stopped further testing

Code: Text
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even when using Windows hot-spot the device states gateway and dns is 192.168.0.1

http://192.168.137.65/cm?cmnd=STATUS%205

Code: Text
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powershell check a few and

Code: Text
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this doesn't appear to change with a static

Added after 34 [minutes]:

my 1 Tasmota device by comparison

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#1309 21803441 09 Jan 2026 05:33

max4elektroda max4elektroda

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Post #1309
21803441 09 Jan 2026 05:33

The "problem" is with json not returning the reality but a predefined answer:

https://github.com/openshwprojects/OpenBK7231...84f90ddf/src/httpserver/json_interface.c#L632

The code for real numbers is in the #if 0 case above ...
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Topic summary

✨ The discussion centers on the development and testing of an open-source firmware project for the BK7231T microcontroller, focusing on creating a cross-platform mini HTTP server, web-based pin configuration, MQTT integration, and Home Assistant compatibility. The project includes a Visual Studio project for Windows and firmware flashing tools like Beken Writer and a Python-based uartprogram. Users report challenges with flashing devices, including issues with firmware size limits (956KB), UART converter compatibility, and power supply stability during flashing. Solutions include using specific UART adapters (e.g., FT232R, CP2102), resetting devices via the CEN pin instead of power cycling, and trimming firmware binaries. The firmware supports devices with BK7231T and BK7231N chips, with ongoing work to add PWM dimmer support, BLE, TuyaMCU protocol integration, and OTA updates. Various smart devices such as WB2S/WB3S modules, smart plugs, LED bulbs, and switches from brands like MOES, Nedis, Hama, and Calex are tested. Users share detailed hardware teardowns, pinouts, and flashing procedures. MQTT topic naming issues related to MAC address usage were identified and fixed. The project emphasizes community collaboration, with suggestions for a Discord server to enhance real-time communication. Additional tools and SDK improvements, including CMake support and BLE integration, are under development to facilitate firmware building and device support expansion.
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FAQ

TL;DR: 100 % flash-success reported on BK7231 T/N modules [Elektroda, p.kaczmarek2, post #19906676]; “OpenBK7231T now boots on three chip families” [Elektroda, p.kaczmarek2, post #19883071] Use QIO image for BK7231N, UA for BK7231T; erase only 0×11000-0×1EF000. Why it matters: a single workflow now replaces vendor firmware on 60 + low-cost IoT boards.

Quick Facts

• Supported MCUs: BK7231T, BK7231N, XR809 (Wi-Fi + BLE) [Elektroda, 19883071] • Recommended UART speed: 921 600 bps for write, 115 200 bps for read [Elektroda, 19857664] • Flash sizes: Typical 2 MB on-chip; config area starts @ 0×1EF000 [Elektroda, post #19893493] • OTA format: .rbl (gzip + AES, served by HTTP) [Elektroda, btsimonh, post #19880525] • Typical power: 5 V @ 500 mA to AMS1117 input for safe programming [Elektroda, ExploWare, post #19853546]

1. Which OpenBK binary should I flash?

• BK7231T/ WB2S/WB3S – use UA.bin via UART bootloader. • BK7231N/ CB2S/CB3S – use QIO.bin at offset 0×0 with –unprotect flag [Elektroda, p.kaczmarek2, post #19890168] • XR809 – build sharedApp and burn with PhoenixMC [Elektroda, 19850458]

2. How do I wire the programmer and reset correctly?

TX of adapter → 1RX pin; RX → 1TX; GND shared.
Pull CEN low, click “Program”, then release CEN to start bootloader [Elektroda, ExploWare, post #19903108]
Supply 5 V to AMS1117 IN or 3 V3 pin; current ≥ 500 mA [Elektroda, ExploWare, post #19853546]

3. Writer stops at “Erasing 0×11000” – why?

The chip is protected. For BK7231N add --unprotect when using uartprogram, or choose BK7231N mode in BKWriter; baud 921 600 often succeeds after 115 200 fails [Elektroda, boozeman, post #19857804]

4. Relay clicks during flashing – safe fix?

A pull-up on RX1 ties the push-button to 3 V3, driving the relay. Remove jumper R33 on Nedis WIFIPO120FWT, flash, then solder it back [Elektroda, boozeman, post #19882233]

5. How can I back-up the Tuya stock firmware?

Run python bk7231tools.py read_flash -d COMx --no-verify-checksum -s 0 -c 512 dump.bin for T/N chips (2 MB, 512 × 4 KB) [GitHub bk7231tools].

6. My BK7231N loses settings after power-cycle.

Disable FAST_CONNECT (RL_SUPPORT_FAST_CONNECT) or use latest OpenBK build ≥ f6c3c8f6 that stores config outside NET_PARAM table [Elektroda, p.kaczmarek2, post #19893493]

7. Does OTA work and how do I host updates?

Yes. Serve *.rbl over HTTP (http-here --host 0.0.0.0 8000). In WebApp → OTA tab → enter http://<IP>:8000/firmware.rbl; device backs up filesystem, flashes, restores settings [Elektroda, btsimonh, post #19880525]

8. Can I change the MAC address permanently?

MAC can be edited in Config → MAC. It is written to efuse on BK7231T and survives reboot [Elektroda, ExploWare, post #19888851] Corrupted flash prevents saving; run recovery image to re-create tables [Elektroda, p.kaczmarek2, post #19888772]

9. What are the default GPIO roles for common plugs?

• Nedis WIFIPO120FWT – P6 LED, P10 Button, P26 Relay [Elektroda, 19883937] • QiaChip Smart Switch (WB2S,T) – P24 Relay, P26 Button [Elektroda, 19906692]

10. How do I compile on Linux or Windows?

Clone SDK OpenBK7231T, then OpenBK7231T_App into /apps. Build: ./build_app.sh apps/OpenBK7231T_App OpenBK7231T_App git (Linux) or Cygwin on Windows; ensure build-essential and gcc-arm-none-eabi installed [Elektroda, boozeman, post #19885620]

11. Is there a no-solder exploit?

Yes. CloudCutter abuses 2019 Tuya SDK bug to OTA-flash BK7231 lights wirelessly; code published February 2022 [khalednassar/tuya-cloudcutter]. "It works on every test bulb so far" [Tom Clement, #19890768].

12. Edge-case: UART2 log shows boot loop only.

Wrong binary type (UA on BK7231N) causes endless boot; reflash with QIO image at 0×0 then AP appears [Elektroda, p.kaczmarek2, post #19890168]

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