The Crew Motorsport depends on that.
ECDSA_P521 is not exactly needed in this case (only ECDH_P521) but that has a lot of common parts and probably makes sense to add at once.
WRT RSA encryption change, the game calls BCryptEncrypt(... BCRYPT_PAD_OAEP) with NULL padding info and output buffer and length, maybe trying to determine the output size this way. The failure here is fatal for that process (while then it is going to use BCRYPT_PAD_PKCS1 with the actual output buffer). Turns out on Windows that works, makes some sense because the size of RSA encrypted output depends on RSA key size only (I added a test with 0 input and no padding just in case). While for decrypt that is different as it is not possible to determine decrypted length without knowing padding algorithm.