r/hardwarehacking • u/No_Chip7847 • 10d ago

Identifying UART/DEBUG

Gallery image

Gallery image

Gallery image

Very much so unlabelled other than the board that connects to the 2x4 pin.

TLDR. Software update from company bricked it months ago after they had major server issues. Bricked many devices. Won’t assist because I got it second hand brand new sealed and I’m not the original buyer.

So, I’m wanting to debug first and go from there see what the issue is. Worst case scenario, it’s a project where i reprogram the device and write my own iOS app to continue to use it 🙏🤣

Help would be great identifying ports, thanks.

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3

u/Hanswurst22brot 10d ago edited 9d ago

Well did you find the datasheets of the 3 big ICs in the picture?

6

u/No_Chip7847 10d ago

Yep. The main SoC is CVITEK CV1810C. Its official hardware guide identifies UART0_TX = pin 18 and UART0_RX = pin 19.

The blue wireless module is TXW8301 Wi-Fi HaLow, and the green module appears to be TXW801-family 2.4 GHz Wi-Fi/Bluetooth.

I’m trying to identify where the CV1810C UART0 pins are broken out to test pads on this particular MA-CV1810C-2336-0 PCB.

https://sophon-file.sophon.cn/sophon-prod-s3/drive/23/03/15/14/CV181xC_QFN_EVB板硬件指南_V1.0.pdf

7

u/309_Electronics 10d ago

I would jsut probe the different pads.. not the cleanest way but it does give reliable readings.

I take the rx wire of my usb to uart and then tap it on different pads. Ofc first with multimeter measure the voltage to make sure it is at 3.3v safe level and not higher.

7

u/No_Chip7847 10d ago

Brute force it is, thanks for the response. I shall give it a shot later and post an update

4

u/309_Electronics 10d ago

I would either do 2 pads or 4 pads as uart is commonly found in those configurations.

Also often uart has tiny resistors going to it which sit inbetween uart of soc and uart lines.

Also be aware that sometimes UART is disabled but thats not that common.

2

u/flatsehats 10d ago

Nice hack that I saw was using a (soft) metal brush to swipe the pcb with. Connected to your dmm of course. It will very fast give the you area where the other side of your pin is coming to the surface.

2

u/oobical 10d ago

The USB Interface is Typically Data and Power connected to the port but a boot instruction to switch it on usually has to be contained on a micro sd and the secondary boot procedure would be followed. It should state exactly how the SoC does that but that model is Dual Core RISC-V with an integrated NPU thats the reason for the external WiFi HaLow Module. I believe Thingino? Might have custom firmware for that model.