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Request for Help – Flashing Della Minisplit WiFi Module (WBR3 on TCWBRCU1)

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  • #241 21761114
    p.kaczmarek2
    Moderator Smart Home  
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    Here is test PR:
    https://github.com/openshwprojects/OpenBK7231T_App/pull/1870
    Command is "Gen X", where X is 0, 1, 2 or 3.
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  • #242 21761123
    vietxtlife
    Level 8  
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    >>21761114 That's what I'm talking about. Thank you.
    So do I just OTA the file? Right?
  • #243 21761141
    p.kaczmarek2
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    well, yes, download artifacts, extract it, find proper ota file your platform and give it a go
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  • #244 21761182
    vietxtlife
    Level 8  
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    >>21761141 Dump question, sorry: extract the file with 7-Zip? Or? Lol I'm so lost
  • #245 21761304
    divadiow
    Level 38  
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    ota to OpenRTL87X0C_1870_merge_5892d33cf0e8_ota.img
    Attachments:
    • OpenBK7231T_App_1870_merge_5892d33cf0e8_OpenRTL87X0C.zip (1.15 MB) You must be logged in to download this attachment.
  • #246 21761331
    p.kaczmarek2
    Moderator Smart Home  
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    Here is step by step explanation:
    https://www.elektroda.com/rtvforum/topic4033833.html
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  • #247 21761454
    vietxtlife
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    >>21761304 Thanks @divadiow @p.kaczmarek2, it seems like it does work. But I need the weather to get a bit cooler so I could really push the mini split to really know if it works. Right now I can't really push the mini split to max.
  • #248 21761976
    p.kaczmarek2
    Moderator Smart Home  
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    That's nice to hear, but how did you verify that it works? With power consumption check? How big is the change?
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  • #249 21762524
    vietxtlife
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    >>21761976 from L1 to L3 about roughly 300 W difference, take that with a grain of salt because I can't be sure if that was the result of the compressor throttle down from the option or it's reached the set temperature (set to the highest possible 88°F) because it was not that cool at the moment. Need to do more tests around Christmas, then it's really cold and the mini split will have to work hard to raise the temperature up without any doubt. I will update when I can be sure that the code works lol, again thank you all for all the work that you guys put in.
  • #250 21764091
    vietxtlife
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    >>21761976 Hey, could we put the GEN option in HA? I want to do automations with GEN function. Thanks, guys
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    #251 21766471
    vietxtlife
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    For anyone who might have messed up their Wi-Fi module during flash, or if you’re looking for a spare one so you can play with it, search for Replacement Internet/BLE Dongle for Pioneer® WYT/WT Series Air Conditioner Heat Pump Systems @ https://www.pioneerminisplit.com. They use the same module, and the firmware's also the same, just got my delivered, jumped on Tuya dev, it's shown exactly what I have from my original module. So if need be you can get replacement now, don't have to go through Della; they’re always out of stock. Anyways, this might help someone.
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  • #252 21775988
    dressyspider
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    Hey @vietxtlif, were you able to get OpenBeken up and running on your mini?
  • #253 21779310
    vietxtlife
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    >>21775988 Yes, got it running OBK; everything works as it should. Thanks.

    Added after 2 [minutes]:

    How do I get Home Assistant to discover Gen option and have Gen option display in Climate like other options (Mode, Swing, Fan, ...). I tried modifying drv_tclAC but can't get Gen to show up in Climate.
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  • #254 21779313
    p.kaczmarek2
    Moderator Smart Home  
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    Is there a HA-specific solution for Gen? Or do you need a generic enum? You could look into enums HA discovery source code. If not, I can try to look into it myself, when I get some time.
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  • #255 21779319
    vietxtlife
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    Honestly, I don't know where to look. I tried, but my skill is next to none; if you could, I really appreciate.
  • #256 21779321
    p.kaczmarek2
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    Probably hass_createSelectEntityIndexedCustom function in OBK source code could help.
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  • #257 21779328
    vietxtlife
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    >>21779321 I will look at that now. Thank you.

    Added after 5 [hours] 35 [minutes]:

    thank you for the pointer, i had made changes to hass.c and hass.h. dont know if the changes are correct and i dont know how to create release to get my ota file to test
    Attachments:
    • hass.h (5.18 KB) You must be logged in to download this attachment.
    • hass.c (45.81 KB) You must be logged in to download this attachment.
  • #258 21779457
    p.kaczmarek2
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    Is this your PR? It does not build yet, you have a compile error:
    GitHub interface showing failed continuous integration checks
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  • #259 21779635
    vietxtlife
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    >>21779457 Yes, that's what I tried. Honestly, I don't know what I'm doing. All I did was search for what you said "hass_createSelectEntityIndexedCustom" and write a new part for GenOptions in the two files I uploaded here. If you could look over those 2 files to see if I messed up somewhere.
  • #260 21779890
    p.kaczmarek2
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    Is the mentioned PR same as uploaded files? If so, there is no need to upload C files, all changes are visible via Github... or are you saying that there is something more in files than in your PR? If so, please submit it to Github, so it's easier to see what was changed.

    Github shows why your changes didn't compile:
    Compilation error in CI showing missing brace in drv_tclAC.c file
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  • #261 21779898
    vietxtlife
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    >>21779890 I have just committed hass.c and hass.h. When I create pull, all checks are errors. Don't know what I did wrong Laptop screen showing a GitHub pull request page for Update hass.c #1895

    Added after 11 [hours] 6 [minutes]:

    >>21779898 help please, i dont know what cause the errors anymore
  • #262 21780258
    p.kaczmarek2
    Moderator Smart Home  
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    Ok, so do you know, that if you click here on "Details":
    Closed pull requests list showing mostly failed CI test results
    You get an error message there:
    Build error showing redefinition and multiple initialization of variable “modes”
    Currently it says:
    Code: text Expand Select all Copy to clipboard
    
 D:\a\OpenBK7231T_App\OpenBK7231T_App\src\httpserver\hass.c(438,9): error C2374: 'modes': redefinition; multiple initialization 

    It says line 438, right? So go to line 438.
    I can see you have variable "modes" declared twice:
    Screenshot showing source code changes in hass.c file on GitHub
    It's good that you are trying to add it, possibly with a help of an LLM, but it would benefit you a lot if you read the error messages.

    Otherwise I'll look into it when I get some time, but I'm just a single person and this project is huge so sometimes I can't really help right away.
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  • #263 21781377
    vietxtlife
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    App settings screen showing GEN Mode with power levels 30%, 50%, and 80%



    So today I managed to capture a graph of the mini split Gen Options operate and how much power it consumed as each Gen option is engaged. Though today is on the extreme side of things, we have -9 °C with our weather, so the mini split is working really hard to heat the room it's in.

    Power consumption chart of shed AC in watts between 8:50 AM and 9:45 AM


    Looking at the graph, each time power usage goes up or down is when I engaged Gen options. With LV1 = 30% the mini split uses roughly 1200 W, LV2 = 50% = 1800 W, LV3 = 80% = 2300 W, and with no Gen = 100% = 2900 W. And because I have the mini split on all day, you can see how much energy can be saved here.
    I control it from the Tuya app, by the way, and the graph is taken from the energy monitor CT clamp that only monitors the mini split circuit
  • #264 21797390
    aleksclark
    Level 1  
    Posts: 1
    >>21566741 Hey, I've got the same module, and just cannot get anything to connect for a firmware dump. I tried `python3 -m ltchiptool flash read -d /dev/ttyACM0 ambz2 /dev/null --length 0x1000` and it times out no matter what combination of pulling A_0 and/or RXD to 3.3 V, power via 5 V, 3.3 V, pulling EN low...

    Can you share how you managed to get a dump/flash?

    Edit: also tried picocom, I get nothing from the LOG_UART. If I hook up to user UART it's definitely alive because I get a single weird char when power applied.

    EDIT: it was my fraking USB adapter. Successfully flashed w/OpenRTL87X0C, now we see if it works!
  • #266 21883997
    vietxtlife
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    No problems, so does every module still good? I got several modules so I switch them around from time to time, to see if any new options created like GEN option. Sadly its wasnt>>21883933
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Topic summary

✨ The discussion centers on flashing and customizing the WiFi module (WBR3 on TCWBRCU1 board) of a Della Optima Series minisplit air conditioner to run OpenBeken firmware for local, cloud-free control. Initial assumptions about the device using TuyaMCU were revised after UART traffic analysis revealed a custom protocol similar to TCL AC units, leading to the development and testing of a dedicated TCL driver in OpenBeken. The user successfully desoldered the WBR3 module, backed up its firmware using appropriate Realtek tools (ltchiptool and AmebaZ2 PG Tool), and flashed OpenBeken firmware. Key datapoints such as power, mode, fan speed, temperature, humidity, and PM2.5 were identified from the Tuya IoT platform, but the device uses a binary packet protocol rather than standard Tuya DPIDs.

The community collaboratively developed and refined the TCL driver, enabling control of power, mode (cool, heat, dry, fan, auto), fan speeds (mapped to Smart Life app presets including auto, mute, mid-low to turbo), swing positions (vertical and horizontal), buzzer (beep) on/off, and display brightness on/off. The driver was integrated with Home Assistant via MQTT with discovery support, allowing control and state feedback. Challenges included correct UART parity settings (even parity), packet parsing, and mapping driver values to Home Assistant entities. The user provided detailed logs, testing results, and UI feedback, leading to improvements in MQTT integration, UI elements for fan speed and swing controls, and bug fixes for state synchronization. The project also discussed future enhancements like better OBK UI integration, thermostat card improvements, and potential DIY thermostat projects using OBK on ESP32 with external sensors.

Overall, the thread documents a successful reverse engineering and firmware replacement effort for the Della minisplit WiFi module, enabling local control with OpenBeken, full MQTT/Home Assistant integration, and detailed community-driven driver development for a non-standard protocol device.
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FAQ

TL;DR: If you have a Della mini split with a WBR3 module, you can flash OpenBeken locally, back up the original 2 MB flash first, and then control cooling, heat, fan, swing, buzzer, display, and even GEN mode. As one developer put it, "It worked!" This FAQ is for owners who want cloud-free control without losing core AC functions. [#21551100]

Why it matters: This thread shows that some Della WiFi modules are not standard TuyaMCU devices, so using the correct Realtek tools and the TCL driver is the difference between a working local AC and a dead-end flash attempt.

Option Chip family Fit/use in thread Main caveat
WBR3 Realtek RTL8720CF/AmebaZ2 Native Della module; fully tested with OBK TCL driver Fragile pads and traces during wiring
WBR1 on TCLWBR Realtek RTL8720CF Also worked after correct VIN/VCC power wiring Needed both 5 V and 3.3 V path active
WB3S Beken Considered compatible replacement for TuyaMCU-style UART layout Must verify 3.3 V, GND, reset, and UART pin match
CB3S Beken Considered compatible replacement with OBK support Same pinout checks as WB3S

Key insight: The Della TCWBRCU1/WBR3 setup in this thread was ultimately treated as a custom TCL serial protocol, not a normal TuyaMCU datapoint bridge. That is why flashing succeeded only after using Realtek-specific tools and why control required the OpenBeken TCL driver, not GPIO templates. [#21549462]

Quick Facts

  • The confirmed stock backup sizes were 384 KB ROM and 2 MB flash, and the 2 MB dump was verified to boot before flashing OpenBeken. [#21544743]
  • The working UART settings for the TCL protocol were 9600 baud, 8 data bits, even parity, 1 stop bit (9600 8E1); parity was a real failure point until fixed. [#21550462]
  • The Della unit discussed was a 9,000 BTU heat/cool mini split on 115 V, 60 Hz power, using a removable USB WiFi/Bluetooth module with a WBR3 soldered to a TCWBRCU1 carrier. [#21536655]
  • Internal target temperature in the TCL protocol is Celsius only, with a usable command range of 16–31 °C; entering 75 or 77 as if they were Fahrenheit produced wrong results such as 81 °F and 84 °F on the indoor display. [#21553236]
  • Reverse-engineered GEN mode testing showed approximate winter heating limits of 1.2 kW at L1, 1.8 kW at L2, 2.3 kW at L3, and 2.9 kW with no GEN limit, based on clamp monitoring. [#21781377]

How do I flash a Della mini split WBR3 WiFi module on the TCWBRCU1 board with OpenBeken step by step?

Use Realtek tools, not BK7231 tools. 1. Back up the stock WBR3 first with the Realtek workflow, because the verified flash dump was 2 MB and recoverable. 2. Flash an OpenRTL87X0C build that includes the TCL driver or update later by OTA. 3. Start the driver with startDriver TCL, then test commands such as ACMode 1, FANMode 3, and TargetTemperature 24. The thread showed this sequence working on the Della 048-TP-9K2V-23S-IN after successful backup and flash. [#21547316]

What is TuyaMCU, and how is it different from the custom TCL serial protocol used by some Della mini split WiFi modules?

"TuyaMCU is a host-MCU protocol layer that lets a WiFi module exchange standardized datapoints with a separate appliance controller, usually over UART." In this thread, that turned out not to be the whole story for the Della mini split. The WBR3 could run OpenBeken, but the AC control path matched a custom TCL serial protocol instead of normal TuyaMCU DPID traffic, which explained why TuyaMCU commands did nothing while the TCL driver worked. [#21549462]

Why does a Della WBR3 module get stuck on "getting bus" in BK7231 tools, and which flashing tools should I use for Realtek RTL8720CF or AmebaZ2 instead?

It gets stuck because BK7231 tools do not support Realtek AmebaZ2 chips like the WBR3. One helper stated plainly that Easy Flasher does not back up or write Realtek chips. The working toolchain in the thread was ltchiptool for backup and AmebaZ2 PG Tool for writing on RTL8720CF/AmebaZ2 hardware, which immediately solved the stalled "getting bus" problem. [#21544726]

What is a DPID in the Tuya ecosystem, and how were the Della mini split datapoints like power, mode, windspeed, and swing identified in this thread?

"DPID is a Tuya datapoint identifier that maps a cloud-visible property to a device function, type, and value range." The thread identified the Della AC datapoints from the Tuya IoT Platform and later from the product data model. Examples included DPID 1 power, 4 mode, 5 windspeed, 113 vertical swing, 114 horizontal swing, and 120 GEN mode, each with enum or value ranges shown by the Tuya schema. [#21536711]

How can I back up the stock firmware from a WBR3 or WBR1 module before flashing OpenBeken?

Back it up with the Realtek toolchain before you flash anything. The proven path was to read both the ROM and full flash, then verify the sizes: the ROM should be 384 KB and the flash dump 2 MB on the tested WBR3. That backup later booted successfully, which gave the thread a recovery path when hardware pads were lifted during rework. [#21544743]

Which OpenBeken commands were used to control the Della mini split after flashing, including ACMode, FANMode, SwingH, SwingV, TargetTemperature, Buzzer, Display, and Gen?

The working commands were startDriver TCL, ACMode, FANMode, SwingH, SwingV, TargetTemperature, Buzzer, Display, and later Gen. Confirmed examples included ACMode 1 for cool, ACMode 3 for fan-only, TargetTemperature 24, Buzzer 0, Display 0, and the test PR command Gen 0 through Gen 3. Those commands were validated progressively in the thread and then exposed to Home Assistant through MQTT discovery. [#21761114]

Why did TargetTemperature seem wrong when entering Fahrenheit values in OpenBeken, and how does the Della TCL protocol actually handle temperature internally?

It seemed wrong because OpenBeken expected Celsius while the indoor display was showing Fahrenheit. The TCL protocol stores target temperature as a 4-bit value for 16–31 °C, so entering TargetTemperature 75 was interpreted as a Celsius-side command, wrapped internally, and produced values like 29 °C, which appeared as about 84 °F on the unit. Once the user switched to TargetTemperature 24 and 25, the display correctly showed 75 °F and 77 °F. [#21553392]

What was the correct UART configuration for the Della TCL mini split protocol on Realtek, including baud rate and parity, and why did parity matter?

The correct serial format was 9600 8E1: 9600 baud, 8 data bits, even parity, 1 stop bit. Parity mattered because the first TCL driver builds used the wrong parity setting, so commands were sent but not understood correctly by the AC controller. Once even parity was fixed, the unit started beeping on valid commands and mode and fan tests began to work immediately. [#21551100]

How do Home Assistant MQTT discovery and the OpenBeken TCL driver work together for a Della mini split, and what commands or settings are needed to make the climate entity appear?

Start the TCL driver first, then trigger Home Assistant discovery. The thread used startDriver TCL and then either Home Assistant discovery from the UI or the command scheduleHADiscovery 1. After that, Home Assistant created a climate entity and additional controls, and later builds added mode, fan, horizontal swing, and vertical swing support to the discovered entity. [#21561364]

What troubleshooting steps helped when Home Assistant showed Della mini split state updates but power-on or mode changes did not work correctly?

The main fixes were driver-side, not MQTT-side. Early on, Home Assistant could show state changes from OBK, but power-on and mode commands were incomplete because the TCL mode parse and mode publishing were not fully implemented. Once the driver parsed AC mode correctly, Home Assistant could both read OBK state and write changes back, including on/off and mode switching. [#21563089]

WB3S vs CB3S vs WBR3 for a Della mini split replacement module — which options were considered compatible with OpenBeken and what pinout checks matter most?

WBR3 was the native tested module, but WB3S and CB3S were both considered workable OpenBeken replacements. The key check was not brand alone; it was whether GND, 3.3 V, reset, and UART matched the original footprint and host board expectations. The thread specifically noted that other GPIO positions may differ, but the basic UART-based control path could still work if those core pins lined up. [#21548807]

How can I capture UART traffic between the WiFi module and the indoor unit MCU on a Della mini split without a full logic analyzer?

You can capture each UART lane separately with a USB-UART adapter if you match the serial settings. One developer explained that you do not need a full logic analyzer to start; you can connect RX to the line you want to observe, set the correct baud, and record module-to-MCU and MCU-to-module traffic independently. For this TCL setup, correct serial settings mattered, especially parity. [#21550113]

What caused the WBR1 TCLWBR board to crash when starting UART-based OpenBeken drivers, and how was the missing VCC or VIN power connection eventually identified?

The crash came from powering the WBR1 incorrectly during bench testing. The user had supplied only 3.3 V for flashing-style setup, but the TCLWBR adapter also needed the VIN/VCC path active from 5 V so the board’s power scheme matched normal operation. Once they powered the adapter board correctly instead of only the WBR1 core rail, the TCL driver started normally and the module worked. [#21579198]

Where can I find replacement Della-compatible WiFi modules like WBR3, WBR1, or Pioneer USB adapter boards if I damage the original during flashing?

One confirmed source was Pioneer’s replacement USB WiFi/BLE dongle for WYT/WT systems, which a later poster said used the same style of module and compatible firmware family. Earlier in the thread, users also sourced WBR3 replacements from AliExpress after damaging traces and pads during desoldering. The practical lesson was to buy a spare before risky rework, because these module pads are fragile. [#21766471]

How was the GEN or generator mode on supported Della mini splits reverse engineered, and what do the L1, L2, and L3 power limits correspond to in practice?

GEN mode was inferred from the Tuya schema, then tested in a custom OpenBeken PR with Gen 0 to Gen 3, and finally validated by watching real power draw. Practical results on one unit were about 1.2 kW for L1, 1.8 kW for L2, 2.3 kW for L3, and 2.9 kW with no GEN limit during cold-weather heating. The user mapped L1, L2, and L3 to roughly 30%, 50%, and 80% compressor power limits. [#21762524]
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