Previous posts have described going to one or more pharmacies with a CDC card and finding a pharmacist who can be sweet-talked into issuing a German vaccination qr code. My mother and sister arrived and did this successfully on Wednesday, December 15. I arrived in Germany two days later. I went to the same pharmacist, who informed us that on the 16th, the national computer system was revised so that it now actually validates the vaccine lot #, and only German lot #s are accepted. They were willing to try for me, and showed me on the screen where the # was rejected.
So no qr code for me. I might try crossing the border to Switzerland on Monday, and if I am able to get a QR code there, I will report back.
In the meantime, I have been to two restaurants who accepted the rapid antigen test I got at the government testing station for ~12 euro. Results for that are delivered only via email, in the form of a link to a QR code.
FWIW, I am in a small town on the shore of Lake Constanz