[BK7231N/CB2S] KMC Smart Tap Mini Teardown and configuration
Remove 4 screws from back.
plate appears to be clipped in place but its not. only friction holds it on.
use something to gently pry along the edge and lift over the plug.
remove the 2 screws from the circuit board and take it out of the case.
remove the CB2S chip from the board with a soldering iron, and solder wick or a heat gun.
careful not to damage the pads as shown in the photo
circuit interferes with chip flashing.
it might be possible to remove a capacitor or other component for same affect
Pins on CB2S chip are clearly labeled.
attach serial programmer to 3.3 GND TX and RX as usual.
Flash chip and reassemble.
Pin configuration
P6 (PWM0) Rel 5
P11 (TXD1) WifiLED_n
P24 (PWM4) Rel 0
P26 (PWM5) Rel 2
plate appears to be clipped in place but its not. only friction holds it on.
use something to gently pry along the edge and lift over the plug.
remove the 2 screws from the circuit board and take it out of the case.
remove the CB2S chip from the board with a soldering iron, and solder wick or a heat gun.
careful not to damage the pads as shown in the photo
circuit interferes with chip flashing.
it might be possible to remove a capacitor or other component for same affect
Pins on CB2S chip are clearly labeled.
attach serial programmer to 3.3 GND TX and RX as usual.
Flash chip and reassemble.
Pin configuration
P6 (PWM0) Rel 5
P11 (TXD1) WifiLED_n
P24 (PWM4) Rel 0
P26 (PWM5) Rel 2
Comments
Hello, your configuration specifies 3 relays and WiFi led, but the device seem to have 4 relays. Is your configuration complete? It is also worth to note the device marking: - Model 30407 - FCC ID... [Read more]
Hi there, I purchased another KMC set which now have the stupid Tuya cbs2 clone. The KMC-30407 were nice an sturdy units as they could be screwed into the socket (instead of just inserted). However... [Read more]
Everything in OBK is fully scriptable, you can easily support that device and script it for each relay to work with single click, double click, or triple click. We already have examples for that in our... [Read more]
Wow that's impressive, didn't know that, thanks! My problem is that I cannot remove the small boards and must flash OTA. I was able to flash all ESP devices with Tasmota OTA, no problem. But most... [Read more]
Tuya-cloudcutter works per device build and profile may not match if Tuya has changed something or updated to newer version. What's your device version according to Tuya app? I did SWP86 teardown and... [Read more]
Regarding https://www.elektroda.com/rtvforum/viewtopic.php?p=20443949#20443949 My units look exactly the same. https://www.elektroda.com/rtvforum/viewtopic.php?p=20803474#20803474 Are the settings/templates... [Read more]
Good morning! I tried the OTA flash you suggested here https://www.elektroda.com/rtvforum/viewtopic.php?p=20828299#20828299 to free my KMC 30407 units (imprisoned by CB2S). But I still get the errors... [Read more]
I don't know if mjspez submitted the 2MB firmware dump anywhere, but in my opinion, this OTA method is not reliable and it's faster to just solder by wires. Why can't you desolder CB2S? Maybe I can... [Read more]
My hands shake too much, also don't have the tools and only 2 hands. I have 6 of these, 2 of the switches and I rather pay more for ESP units which work OTA than solder/destroy around. Sorry. That's... [Read more]
Ok then you have to try cloudcutter profiles one by one, like it's said in the post I linked. I could flash the devices for you, but I think that shipping from Germany may be too expensive for that to... [Read more]
Ok, will try, when you talk about profile, do you mean the pin assignment? Or is it about the actual program being sent to the unit? Happy Thanksgiving to your side of the world.... [Read more]
I was unable to flash OTA! Tried all options. So I opened the unit and was finally able to get the flash. Attached is the 2MB flash. I made a schematic of the logic part, to see if the stupid CB2S... [Read more]
Thank you, this schematic is very informative. I'll see what I can do about OTA for that device and reply here again. If I don't reply, please remind me. Added after 7 [hours] 9 [minutes]: The... [Read more]
Happy the schematic could help, made it double worthwhile, thanks. Will try out your fine code later. Didn't know these came with WB2S. OP and me have the CB2S. Originally these came with ESP TYWE3S,... [Read more]
I've had to consult about that problem, but now I know that you need to run it with the -r flag, you have NetworkConnection profiles that are not getting properly removed. Added after 1 [minutes]: ... [Read more]
You are AMAZING! How did you find that? I searched myself and could not find anything, bravo!! So I removed many many files from system-connections. But then somehow Docker wasn't working, hat to... [Read more]
Does the problem happen on only one device? So IP 192.168.4.1 is not reachable? Can you try to connect to AP with other device? [Read more]
I opened another of these, but added the AP info sudo ./tuya-cloudcutter.sh -r -s tasmot 12345678 It didn't connect to tasmot, but at least this unit does react to the switch. All realys turn still... [Read more]
it says wlan0: Could not connect to kernel driver ?? Added after 7 [minutes]: The 30407 actually got an IP from tasmot! I can ping it, it's very slow, ~40-60ms, but it reacts. However if I go... [Read more]