Hi. Have same problem. Where did you find firmware for P3EX? i have stacked on Load the firmware-file for ProfiLux by clicking onto „Open“, navigate to the firmware-file and select it. The file name of the firmware starts with „ProfiLux3_“ and ends with „.mhx“, e.g. ProfiLux3_V515_GER_ENG.mhx
No idea where to find that file. On ghl website i have seen only firnware for Profilux 2
Best regards