Bip39 Checksum. Push X to abort passphrase application and keep enhancing the passphrase. Picking out CANCEL immediately after an abort will stop the procedure. What constitutes a "very good wallet" is one which has very clear, straightforward to obtain documentation on supported BIP benchmarks, derivation paths, and recovery processes. This https://socialtechnet.com/story4118865/bip-39-https-linktr-ee-bip39-not-known-factual-statements-about-ian-coleman-bip39