doc: secure boot: Fix relative reference to key generation step

docs/en/security/secure-boot.rst

@@ -117,7 +117,7 @@ Configuration "Secure Boot: One-Time Flash" is the recommended configuration for
 
 However, an alternative mode :ref:`Secure Boot: Reflashable <CONFIG_SECURE_BOOTLOADER_MODE>` is also available. This mode allows you to supply a binary key file that is used for the secure bootloader key. As you have the key file, you can generate new bootloader images and secure boot digests for them.
 
-In the esp-idf build process, this 256-bit key file is derived from the app signing key generated during the generate_signing_key step above. The private key's SHA-256 digest is used as the secure bootloader key (as-is for Coding Scheme None, or truncate to 192 bytes for 3/4 Encoding). This is a convenience so you only need to generate/protect a single private key.
+In the esp-idf build process, this 256-bit key file is derived from the ECDSA app signing key generated by the user (see the :ref:`secure-boot-generate-key` step below). This private key's SHA-256 digest is used as the secure bootloader key in efuse (as-is for Coding Scheme None, or truncate to 192 bytes for 3/4 Encoding). This is a convenience so you only need to generate/protect a single private key.
 
 .. note:: Although it's possible, we strongly recommend not generating one secure boot key and flashing it to every device in a production environment. The "One-Time Flash" option is recommended for production environments.