@Zax Hey thank you very much for this quick answers.
I will check at home in the next days.
If I understand you correctly. It doesn't matter which Kind of Nano (-compatible) chip I buy? Also It doesn't matter which Kind of boodloader is installed?
So buying a new Nano chip, replace the old one, and Flash it with help of your T2 laser Software with the firmware GRBL 1.1e will work? (Sorry for those bad questions but thats all new for me.)
Thanks a lot