Ok, thanks for help and pointers- got it to work.
As noted above. New TCU2 display comes in a default factory firmware, locked to 15kmh. There is no way to upgrade it without an actual levo that originally came with that tcu. You need to do the upgrade on gen3 bike and then plug it into your gen2. Can’t do it on Gen2 via MC , it has to be done via the dealer workstation. Took about 5 min.
I found a very friendly dealer who was willing to help (my next bike will be purchased from them

) . I no longer have a swap warning messages and I can upgrade all the components (motor, battery and tcu) directly via MC once paired. I did have to reinstall the app.