Orbi Pro SRR60 Router not starting after firmware update

Today my iPhone Orbi App suggested to upgrade the firmware of my Orbi Pro (SRR60 router) system.

The Router itself did not come back up.

The power LED is solid green (even immediately after power on).

The reset button does not do anything at all.

The last working firmware was the last but one (not sure about the number).

All satellites show purple color halo. The router has no halo at all.

I tried disconnecting the router from all Network and power, reconnecting it to power, resetting it. Nothing works.

Only a steady green power light.

Any ideas?

Thanks a lot,

Thomas