TFT35v2+SKR1.3+Marlin2.0 - no Printer attached

[thechoozen]

Hello!
i hope someone could help us. We have upgraded an CR10 Clone with the above mentioned components. First we had the no printer attached error. After a llonger search on google we found a video which helped us to solve the error (which showed us which changes we had make in Marlin and what we didn´t need to change).
After that we got it running without the error and we were able to move alll axis and everything was fine.
Then we decided to upgrade the Extruder and Hotend and left the printer alone for a few days without touching it. After the new parts arrived we swapped them with the old parts and powered the machine on and there is the "no printer attached" error again.
In the time between we didn´t change anything on the firmware and we didn´t touch any cable, so what am i missing here ?
Why is the error occuring again and how can i finally get rid of it ?

Edit: I just flashed the firmware of the Board and Display (again) to the last working version, but it still says no printer attached . Now i have the exact same software versions running on board and display like the last time when the message disappeared after a few seconds running. But now the errors stays......what am i missing ???

[Jean-Michel-90]

Hello,
When i connected for the first time m'y TFT 35 to my mini e3 i also got "no priter attached" issue and i must change the baudrate in accordance with the one in Marlin.
I don't remember procedural but usually, you should save parameter in eeprom if you want to retrieve configuration after power up.

Hope it could help you