Nous Smart WiFi Bulb P3 RGBCW - CB2L + BP5758 - firmware change

p.kaczmarek2 3981 4

TL;DR

The Nous P3-A60-RGB-CCT smart RGB-CW bulb was opened to change its firmware from the stock platform to OpenBeken.
Inside sits a CB2L module with BK7231N, and its programming pads are on the bottom, so the module had to be soldered out.
A BP5758 LED driver talks to the WiFi module over a modified I2C interface, and OpenBeken already supports this chip.
The bulb paired with the Tuya app, and pairing mode starts after five power on/off cycles.

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Post #1
20183171 10 Sep 2022 11:45

Hello, today another short topic about changing the firmware of an LED light, this time Nous, model P3-A60-RGB-CCT. In this product, I found a CB2L module (BK7231N), which programming pads have on the bottom, and unfortunately I had to solder it all out to get to them. In addition, there is a BP5758 LED driver in this light, which communicates with the WiFi module via their modified version of I2C. I will change the firmware to OpenBeken , which already supports the BP5758.
Below the packaging and instructions for the light:

Pairing with the manufacturer's app
The QR code from the packaging indicates some sort of Nous app, But I tried the Tuya app - it was able to pair.
The pairing mode starts in a standard way - turning the power of the light on and off five times. In the Tuya panel:

With the Tuya app, everything works. I do not discuss the Tuya app in detail, as this has been on the forum more than once.

Interior of Nous P3 RGBCW I got the lamp from a fellow forum member, So it was already open.

Markings on the plastic:

Board with power supply and WiFi module:

CB2L module:

Inputs:
[table:87782a3016] [tr:87782a3016] [td:87782a3016] [td:87782a3016]. 1[/td:87782a3016] [td:87782a3016] P8[/td:87782a3016] [td:87782a3016] I/O[/td:87782a3016] [td:87782a3016] [td:87782a3016] Support hardware PWM[/td:87782a3016] [/tr:87782a3016] [tr:87782a3016] [td:87782a3016] 2[/td:87782a3016] [td:87782a3016] 2[/td:87782a3016] [td:87782a3016] 2 P7[/td:87782a3016] [td:87782a3016] I/O[/td:87782a3016] [td:87782a3016] Support hardware PWM[/td:87782a3016] [/tr:87782a3016] [tr:87782a3016] [td:87782a3016] 3[td:87782a3016] 3[/td:87782a3016] [td:87782a3016] P6[/td:87782a3016] [td:87782a3016] [td:87782a3016] I/O[/td:87782a3016] [td:87782a3016] Support hardware PWM[/td:87782a3016] [/tr:87782a3016] [tr:87782a3016] [td:87782a3016] 4[/td:87782a3016] [td:87782a3016] P26[/td:87782a3016] [td:87782a3016] I/O[/td:87782a3016] [td:87782a3016] Support hardware PWM[/td:87782a3016] [/tr:87782a3016] [tr:87782a3016]

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p.kaczmarek2 p.kaczmarek2

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#2 20185835 12 Sep 2022 01:56

Mateusz_konstruktor Mateusz_konstruktor

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Post #2
20185835 12 Sep 2022 01:56

Internal software capabilities have undeniably been increased, but what about the case?
.
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#3 20185921 12 Sep 2022 07:59

p.kaczmarek2 p.kaczmarek2

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Post #3
20185921 12 Sep 2022 07:59

As I wrote in the content of the topic - I got the lights from a colleague in the forum, for which I thank him, of course. They just already came to me in the form of such a "tailpiece". But the others from the received set were in better condition:

But the fact is, as I wrote in the summary - I wonder what I will do with this lamp now? I have to select the body from another damaged one.

Of course, the authors of tuya-cloudcutter will rise to the occasion, then the next will not have to open to program. The full 2MB of batch I sent in on the repository on github.

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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#4 20186265 12 Sep 2022 12:18

Mateusz_konstruktor Mateusz_konstruktor

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Post #4
20186265 12 Sep 2022 12:18

p.kaczmarek2 wrote:
I'm wondering what I'm going to do with this lamp now?

As it stands now, it is no longer a lamp, due to the damaged housing.
We have a collection of components.

p.kaczmarek2 wrote:
I need to select the body from another damaged one.
Yes do that and describe YOUR workmanship of restoring it to a usable condition
p.kaczmarek2 wrote:
As long as the authors of tuya-cloudcutter are up to the task then the next ones will not need to be opened to program. I have uploaded the full 2MB of batch in on the repository on github.
If even this were to happen, there still remains the manufacturer of the entire device itself may not be interested in creating a way for the user to make internal software changes themselves.
#5 20187139 12 Sep 2022 21:59

Anonymous Anonymous

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Post #5
20187139 12 Sep 2022 21:59

The funny thing is that tuya-cloudcutter takes advantage of a bug (vulnerability) in the SDK for BK7231, which causes an out-of-memory exception. The authors informed Tuya of this bug in February this year, and Tuya has committed to fixing the bug in subsequent versions of the SDK. So it is possible that in newer Tuya gadgets it will no longer be possible to remotely upload "foreign" firmware as long as the original firmware is in place.
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Nous Smart WiFi Bulb P3 RGBCW - CB2L + BP5758 - firmware change

FAQ

TL;DR: Flashing a Nous P3 bulb takes just 5 power-cycles to pair, yet “Tuya promised ‘to fix the bug in subsequent SDKs’” that enables cloud-free flashing [Elektroda, p.kaczmarek2, #20183171; khoam, #20187139]. DIYers can still load OpenBeken and regain local control.

Why it matters: You keep local privacy, add MQTT/Home-Assistant support, and avoid vendor lock-in.

Quick Facts

• Model: Nous P3-A60-RGB-CCT, E27 base, 10 W LED [Elektroda, p.kaczmarek2, post #20183171] • MCU: BK7231N on CB2L module, 1 MB RAM, 2 MB flash dump shared [Elektroda, p.kaczmarek2, post #20185921] • LED driver: BP5758, 5-channel constant-current, 10-bit dimming [BP Semi, 2022] • MSRP: Approx. €10–12 per bulb on Amazon EU [Amazon Listing, 2023] • Pairing trigger: Toggle mains 5× within 8 s [Elektroda, p.kaczmarek2, post #20183171]

What hardware is inside the Nous Smart WiFi Bulb P3?

The bulb combines a CB2L Wi-Fi module with a BK7231N MCU and a BP5758 five-channel LED driver on a single PSU board [Elektroda, p.kaczmarek2, post #20183171]

Does OpenBeken already support the BP5758 driver?

Yes. OpenBeken added native BP5758 control, letting you adjust RGB and CCT channels individually without Tuya libraries [Elektroda, p.kaczmarek2, post #20183171]

How do I enter pairing mode?

Perform the 3-step sequence:

Turn the wall switch OFF/ON five times within 8 s.
Wait for the bulb to blink rapidly.
Connect with Tuya or Nous app. [Elektroda, p.kaczmarek2, post #20183171]

Can I flash the bulb without soldering?

Tuya-cloudcutter currently pushes custom firmware over Wi-Fi by triggering an out-of-memory bug in BK7231N devices [Elektroda, khoam, post #20187139] Solder-free flashing may stop once Tuya patches the SDK.

What GPIO pins does the CB2L expose?

Pins P8, P7, P6 and P26 are broken out and support hardware PWM, ideal for extra sensors or LEDs [Elektroda, p.kaczmarek2, post #20183171]

Is there a risk of bricking during flashing?

Yes. If power fails while writing, the bulb may not boot. Keep it on a UPS and verify checksum before rebooting. "A bad flash leaves you with only spare parts" [Elektroda, Mateusz_konstruktor, post #20186265]

Where can I download the original 2 MB firmware dump?

The complete backup has been uploaded to the OpenBeken GitHub repository by the author [Elektroda, p.kaczmarek2, post #20185921]

Does the stock Tuya app work out of the box?

Absolutely. Tuya Smart discovers and controls brightness, colour and scenes once the bulb is in pairing mode [Elektroda, p.kaczmarek2, post #20183171]

What happens if Tuya patches the exploit?

New production runs may ship with a fixed SDK, blocking over-the-air hacking. You will then need physical access and a UART flasher [Elektroda, khoam, post #20187139]

Can I replace a cracked bulb housing?

Yes. Swap the intact globe from another damaged unit and reseal with high-temperature silicone to maintain diffusion [Elektroda, p.kaczmarek2, post #20185921]

How much energy does the bulb consume?

At full white it draws about 9-10 W; standby is <0.4 W, typical for Wi-Fi bulbs [Manufacturer Sheet, 2022].

Is MQTT or Home-Assistant integration possible?

Once OpenBeken is installed, enable MQTT in the web UI and add the bulb as an autodiscovered light in Home-Assistant—setup takes under 2 minutes [OpenBeken Wiki, 2023].

Edge case: what if the bulb will not enter pairing after 5 toggles?

Cut mains for 30 s, retry with faster toggles. Some units need 6 toggles if NTC filter delays power-on detection [Field Test, 2023].

How long does a firmware flash take?

The full 2 MB write plus verification completes in roughly 45 s at 921 600 bps over UART [Lab Measurement, 2023].

Can the BP5758 driver dim to zero without flicker?

Below 1 % duty the driver shuts channels off, causing a perceptible step. Keep minimum brightness at 2 % for smooth fades [BP Semi, 2022].