How to turn your Core2 into a paperweight/magnet, a cautionary tale.

  • Hello Friends! First time posting, so I wanted to introduce myself. What better way than to tell a tale of curiosity that almost killed the cat... or in this case my brand new Core2.

    It all started as I was reviewing the documentation and the schematic. I noticed that the M5Stack Documentation site lists the ATECC608A, which I cant for the life of me find on the schematic. ( So my curiosity got the best of me and I decided the best course of action would be to take the Core2 apart to try and find the chip! I mean there are a couple screws on the back, it cant be that bad, right?!

    Well, part 1 of my assumption was true. I took the 4 screws on the back off and carefully separated the back from the front. This part was relatively straight forward. The only surprise being to make sure that you catch the EXT board when you separate the parts because it'll come off quick. I sat and marveled at the board. Very clean and very well done. With the help of my cellphone camera, I was able to zoom in close enough to identify all the IC's on the board and the schematic. I should have stopped here, but I didn’t find what I was looking for. It was about then I noticed there were 2 additional screws at the bottom of the board.

    If you decided to follow along on my journey. STOP. TURN BACK. DO NOT PASS GO. This is where things start getting sketchy. You should know, I'm no special anyone, I have no tools or expertise that would help on this journey. Just curiosity and sausage fingers. Undoing the 2 screws was pretty simple, but then trying to figure out how to release the main board became problematic. I finally figured out that you have to remove the speaker and the vib motor in order to slide the board back enough to allow it to clear the notch. Once that happened, I figured, "I'm in the clear" so I opened it carefully, but just a little too far. It's then I discovered that the LCD and touch ribbons are now disconnected from the two tiny ribbon connectors. In case you were wondering, the ATECC608A isn’t on the backside of the main board. Besides those connectors were some test pads and the button battery. (It's soldered in, and looked like a MS614).

    After a LOT of time very carefully getting the ribbons put back in... which I somehow was able to do (again, see the part about having sausage fingers...) It came time to reassemble. All was going well, thought I had everything back. Reattached the battery, ran though the Factory Test Program and everything worked BUT the vib motor. Shoot. So after disassembling the 2nd time, I found that I hadn’t routed the wires properly and managed to knock the positive side of the motor off of the main board. Thankfully, the only tool I did have handy was a soldering iron with a needle tip. After some creative use of a cellphone zoom and a helping extra hand, I managed to get everything reconnected, reassembled and everything passed the factory test program on the next boot. YAY!

    Moral of the story... don't take your Core2 all the way apart (or probably apart at all...)

    Addendum: After reading the datasheet for the ATECC608A it very clearly calls out that "the part mark for all crypto devices is intentionally vague." So going back though the pictures I took, there appears to be a chip that matches the description just to the side of the USB-C port. I'm not sure, but the pad count is correct and its the right size so ** shoulder shrug emoji here ** ?

    If anyone has any information about where this shown on the schematic or if you can use the chip at all from code, please let me know!

    Nice to meet you! Thank you and enjoy your Core2!

  • Hello @revta

    thank you for sharing your experience.

    Re ATECC608A: I did not notice the link in the M5Core2 documentation until now.

    However running an I2C scanner on M5Core2 doesn't reveal such a device (which by default should have address 0x35). All devices the scanner detects are: 0x34 (AXP), 0x38 (Touch), 0x51 (RTC) and 0x68 (IMU).

    The 8 pin IC close to USB-C you referring to I think is part of the protection circuit for the SD card - but I could be wrong about that.

    At this point my conclusion is that the ATEC608A never made it into the final design.

    Happy Stacking!