Is really nobody having an answer to my very basic issue? I thought static IP issues have been solved with the last firmware updates. Thanks.

Ok, I will send this c*** back.

  @podersol1 It would be very helpful if you could provide screenshots of the configurations you have. I understand your position and I understand that er605 has some errors that should not exist knowing that it is tp link. I have an er605 and it does let me assign a static IP without problems but we need more information to help you  

  @Josvell thank you for your reply. I think with my description everyone should have a full picture about the configuration. What kind of screenshots or additional information do you need? 

  @Sunpower1 screenshots of the information you describe. It will be very useful because there could be something you are omitting. Could you provide capture of the dhcp configuration configuration when you try to assign static ip. Is the er605 controlled by omada or is it directly by the er605?