CrossRoads: PaulS is referering to the Reset Enable trace that is between 2 solder pads.
I also found the hint to place a capacitor between GND and RESET ( + side to RESET ), found a 47µF in my box, and this has the same effect:
The Reset pulse from USB seems to come through a pulldown resistor and is too short to empty the capacitor enough to get RESET signal low.
For uploading, either remove the capacitor or keep the Reset button pressed until TX led flashes, which is probably about the same time as your message hint. Seems not very critical timing. I got it immediately.
Could it be possible to fine tune the capacitor to properly detect a different duration between the upload reset signal and the Serial Monitor duration?
Or are they the same length?
I don't like to scratch or iron my tiny and brand new Arduino baby yet.
Rather prefer a breadboard solution if there's no immediate "Protocols and Devices" solution.
Thanks for your helpful replies, PaulS and CrossRoads !