@evoprint3d ok, the PanelDue thing is here:
https://duet3d.dozuki.com/Wiki/Connecting_an_LCD_control_panel#Section_PanelDue_config_g_setup_for_RepRapFirmware_Num_3
"Note: Using a PanelDue with Duet 3 and Duet 2 and RRF3 will require M575 P1 S1 B57600 being present in config.g. Previously in RRF2 this was assumed as the default, so your config from RRF2 may not include it." Maybe this is missing
