bip-schnorr and HD Key Derivation
Is it safe to use HD Key Derivation with bip-schnorr?


Yes, it is designed to be.


  The bip mentions that you should not throw away the first byte of a generated key.


Perhaps this is worded confusingly.

It means that you can't use a variant of the signature scheme, which uses full public keys, but then throws away one byte of the public key at verification time. Doing so would just result in 50% of the signatures being rejected (because the public key wouldn't match what was used at signing time).


  It sounds like its safe for the prover to drop the extra byte but not the verifier. 


This has nothing to do with safety, but about correctness.