Hi @polemon,
I think the reason is option you checked (Erase All Data/Code Memory) in the “Step 2 - Erase” part.
When this option is checked, it will erase all data including MAC address and write a new firmware.
If you want to update the previously used firmware, set as follows.
If the chip worked before, I think you have a MAC address. You have to input the MAC address to the device.
Please refer to the link below for setting options and how to insert the MAC address.
- Using serial: [WIZ107/108/750SR Series] How to insert MAC address?
- Using MAC Tool: : Developer's Guide-[EN] | WIZnet Document System
