Hi Jardar, The docs for secure boot are published/duplicated here: https://docs.pycom.io/chapter/advance/encryption.html Encryption key can't be changed, nor re-generated (that's why they should be kept safe). The 3 times limitation is valid just in the following case: the firmware binaries are written not-encrypted using USB (uart), and the ESP32 encrypts all the partitions marked as encrypted (and an ESP32 efuse has to burned. In all the other cases, like OTA update, ftp transfer, the encryption/decryption is made transparently, without the encryption counter being increased.

@this-wiederkehr I think it the same way as you do. There is no parameter named as server_hostname in the docs.