I think that according to the Nuremberg Law, if you were half or less Jewish by blood, and declared yourself a Christian, then you were legally Aryan.
Hitler's chauffer, Emil Maurice, was half Jewish.
Emil Maurice 19 January 1897 – 6 February 1972) was an early member of the National Socialist German Workers' Party (Nazi Party) and a founding member of the Schutzstaffel (SS). He was Hitler's first personal chauffeur, and was one of the few persons of mixed Jewish and ethnic German ancestry to serve in the SS, being declared an honorary Aryan by Adolf Hitler in 1935....
Himmler recommended that Maurice be expelled from the SS, along with other members of his family. To Himmler's annoyance, Hitler stood by his old friend. In a secret letter written on 31 August 1935, Hitler compelled Himmler to make an exception for Maurice and his brothers, who were informally declared "Honorary Aryans" and allowed to stay in the SS.
Nope. That's incorrect. It didn't matter if you had converted to Catholicism, according to the Legal Mischling (Mixed Blood) Test A , If you had two grandparents who were Jewish, you were considered to be a "Mischling First Class." A “Mischling Second Degree” is a person with one Jewish grandparent and three non-Jewish grandparents.
Further, from Esther Littman Gorney who was a Holocaust survivor:
According to the Nuremberg Laws of 1935, Jews were divided in four categories:
1. “Volljude” or full Jew: a person who had either four or three Jewish grandparents
2. “Geltungsjude” or self-declared or believing Jew: a person who had two Jewish grandparents and two non-Jewish grandparents (Aryan) and was raised in the Jewish religion
3. “Mischling First Degree”: a person with two Jewish grandparents and two non-Jewish grandparents, who was either baptized and brought up Christian or practiced no religion
4. “Mischling Second Degree”: A person with one Jewish grandparent and three non-Jewish grandparents, who was baptized and raised Christian or with no religion
According to Littman Gorney:
"The Nuremberg Laws dictated that Jews could only marry within their own category. A Mischling, for example, could not marry either a full Jew or a Christian. I was a Mischling First Degree because I was the offspring of parents who were also labeled Mischling First Degree. That means both parents had Jewish fathers and non-Jewish mothers. Both my mother and father had been baptized as Lutherans."
Link to full article:
According to Wikipedia, and another source, Maurice was one-eighth Jewish. His great-grandfather was a Jew. I see that Himmler tried to get him kicked out of the SS because of that, but Hitler told him to back off, and leave Maurice, and his brothers alone.
Hitler did give exemptions to some half and quarter Jews that served in the military. In order to keep the exemption, they would have to prove themselves as a soldier. He also gave exemptions to half and quarter Jews that had distinguished themselves in WWI. But these exemptions were only worthwhile during the war. One of the exemptions he gave to a Private reads that: "After the war, I will decide whether to declare _______ of German blood according to his performance as a soldier.
Signed, Adolf Hitler"
Hitler was never going to grant any Jew, half or quarter, permanent German blood status.