i has a problem with my WAS7500/12

the system was starting Firmware Upgrade and stop working.

After one hour, i power-reset the system.

now after Power - Plugin its show

- Starting up, please wait

- Upgrade failed, it will start again

after mostly 1 minute the display show

Center not found
(Restore settings on Center, connect Center with Ethernet cable)

i try everything as written in the manual without success. I also try to direct connect the WAS7500 to the PC with a cable but the PC cannot found the WAS7500

Is there a posibility to do the firmware upgrade with other methods like with USB Stick?

thanks for any tips!