Connect the Ethernet cable to the printer and observe the ASCII GUI. Normally, some values change every second and should continue to do so after you plug in the cable. If the firmware freezes, double-check the BIOS settings.

During boot, the firmware displays various information (as shown in the second photo). If the printer consistently freezes at a particular stage upon rebooting, that may be the issue. Unfortunately, the only way to reboot from frozen firmware is to turn the printer off and on again.

The printer should now function correctly. You should be able to connect to it immediately with ZPrint or 3DPrint software because all settings were saved on its internal HDD. Keep in mind that the new mainboard has a different MAC address, so network configuration changes may be necessary in your institution/workplace.