Upgrading Ender 3 Pro motherboard from 4.2.2 to 4.2.7

Ender-3 V3 Printers
1

Hi,

I have an Ender 3 Pro with a Creality 4.2.2 motherboard and BLTouch which has been running great for the past year using Octoprint.

I recently decided to upgrade the motherboard to the 4.2.7 but once installed I can’t get the serial to work with Octoprint, I have tried many things with no luck, I even plugged the serial connection from a laptop to the Enter 3 Pro serial and it did not pickup the serial port.

I have swapped the board back to the 4.2.2 and its all working again.

I used the Marlin Ender 3 Pro firmware with BLTouch and did not change any settings.

Could it be a faulty board or did I get something wrong?

The board CPU is STM32F103RET6, and the SD card has (T6) written on it which is odd?

Thanks