Issues Flashing SM-301-U-PA20 Xenon Powerstrip with CB3S Chip Using Pogo pin Jig

Hi All,

I'm trying to flash an SM-301-U-PA20 Xenon powerstrip that uses a CB3S chip. I'm not excited about soldering so I've been trying to use the pogopin jig that I use to flash many of my ESP8266-ish devices. So far, I've had no luck. I'm using ltchiptool, trying to just get the chip info or read the flash.

Here's the jig:

I figured, based on comments in the forum and the GitHub issues, that something else on the board was getting in my way and had given up.

Looking around this forum, I see a couple of references to folks flashing very similar devices by soldering to the board (e.g. https://www.elektroda.com/rtvforum/topic3963570.html#20479666 by @gcole) so I've been thinking again about what's been giving me problems.

There's some sort of goop over the contacts on the chip (see photo), I thought it was left over from the soldering process, but I'm wondering if it's epoxy or something that's intended to prevent people like me from getting access?



If I put probes from a multimeter between the 3.3v and the ground pins on the chip, should I see conductivity (a circuit)? I'm not, which makes me suspect that I'm not actually touching the pins....

Thank you for any suggestions!

g.

Added after 37 [minutes]:

A bit more exploring with my meter's continuity mode. I can hold a probe onto the metal shell of the module and the ground pin and get a signal, and I can find pins elsewhere on the board that also give me a beep. So, it seems like the probe is making a reasonable connection to the chip.

Likewise, I can hold a pin to the 3.3v pin and explore various chips. Some of them report values that change when I apply/remove the probe to the 3.3v pin (not sure if it's measuring ohms of resistance or ???). I never get a beep, but since the value changes I assume I'm making contact.

This all suggests that the chip hasn't been tamper-proofed and something else is going wrong. Suggestions?

If the pins have continuity then I would suggest you have the connection correct and it may be other things.

Often you can see some serial activity if you use something like telnet which could be a good indicator before reading flash.

But otherwise what's your flashing procedure? The timing for bridging GND to CEN can be quite crucial also have you tried using Easy UART Flasher? https://github.com/openshwprojects/BK7231GUIFlashTool

Baudrate could be another factor, sometimes setting it lower has helped.

Another item may be if it's getting enough current, a good tell for this is if powered using the jig does it connect to via stock app e.g. tuya.