M300 DUAL - update 2.2.3 to 2.5.4. - printer is not responding

I have M300Dual. I tried to update from 2.2.3 to 2.5.4.
Earlier, I set up an internet connection and registered the device. The update reached the moment when the display read (if I remember correctly) “completation 100%”. it also said that this could take a while. I waited about 2 hours in this state. Nothing has changed. I turned off the printer with the main switch. After turning it on again, the sign Zortrex appeared and after a while “Z” with the light spinning around. I left it for about 1.5 hours but nothing changed.
I downloaded version 1.0.4 to the USB. This time he asked whether to update to an older version.
What do you propose to do? I am asking you not to mix up more.

Hello @MDzwonkowski86,

Please follow the troubleshooting manual and check the connections. If the issue still persists - please record a short video of the problem and contact us via support form. We will provide you with further help.

Best regards,