I have the PCBs and am testing it. I noticed, that on your PCB one connection to the 4-pin i2c screen version (SDA) is not populated, there is no trace from the mcu. If you program it from the deividAlfa and want to simply use parts from the original KSGER T12 V2, the screen will not work. One need to modify the source code, the PCB or solder a little wire (which is ofc quicker and easier in my case
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
).
While examining the PCB, I also noticed that a single quite thin trace on the top layer is used to control the heater. In the original design, the power trace is double-layered with 2 vias. I suggest to consider it in future revisions.