Am I correctly understanding TLS 1.2 PRF (Pseudorandom Function)? According to RFC 5246 Section 5

PRF(secret, label, seed) = P_&lt;hash&gt;(secret, label + seed)


and

P_hash(secret, seed) = HMAC_hash(secret, A(1) + seed) +
                       HMAC_hash(secret, A(2) + seed) +
A(0) = seed
A(i) = HMAC_hash(secret, A(i-1))


According to my understanding first iteration of P_hash is

P_hash(secret, seed) = HMAC_hash(secret, A(0) + seed) and A(0) = seed


So,

P_hash(secret, seed) = HMAC_hash(secret, seed + seed)


Is it correct? Or is the first iteration rather

P_hash(secret, label) = HMAC_hash(secret, A(1) + Seed)


and

A(1) = HMAC_hash(secret, A(0))
Simply by substituting A(0) in A(1), and then A(1) in P_hash, one obtains your second suggestion. I don't understand how you came up with the first one?