Well, I just tested it 10 minutes ago 
Will try again!
Hmm, no cigarā¦ Still ECDSA curve P-384 not allowed Iām afraidā¦
Also, prime256v1 is not allowed, so itās not P-384 specific: ECDSA curve P-256 not allowed
Adding brainpoolP512r1 (obviously a not supported, but prime curve) to the CSR gives the following error: Error: urn:acme:error:malformed :: The request message was malformed :: Error unmarshaling certificate request
Same for āsect283r1 : NIST/SECG curve over a 283 bit binary fieldā, so I guess everything unknown is hard to unmarshallā¦?