mcuboot: Fix mising cmake changes

Uncommitted changes to image_signing.cmake prevented HMAC-SHA512 usage
with ECIES-X25519, in image signing.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit c3e5321)

Author: de-nordic

cmake/sysbuild/image_signing.cmake

@@ -196,8 +196,18 @@ function(zephyr_mcuboot_tasks)
           CACHE FILEPATH "Signed and encrypted kernel bin file" FORCE
       )
 
+      # Signature type determines key exchange scheme; ED25519 here means
+      # ECIES-X25519 is used. Default to HMAC-SHA512 for ECIES-X25519.
+      # Only .encrypted.bin file gets the ENCX25519/ENCX25519_SHA512, the
+      # just signed one does not.
+      # Only NRF54L gets the HMAC-SHA512, other remain with previously used
+      # SHA256.
+      if(CONFIG_SOC_SERIES_NRF54LX AND CONFIG_MCUBOOT_BOOTLOADER_SIGNATURE_TYPE_ED25519)
+        set(imgtool_hmac_args --hmac-sha 512)
+      endif()
+
       set_property(GLOBAL APPEND PROPERTY extra_post_build_commands COMMAND
-        ${imgtool_sign} ${imgtool_args} --encrypt "${keyfile_enc}" ${imgtool_bin_extra} ${unconfirmed_args})
+        ${imgtool_sign} ${imgtool_args} ${imgtool_hmac_args} --encrypt "${keyfile_enc}" ${imgtool_bin_extra} ${unconfirmed_args})
     endif()
   endif()
 
@@ -229,6 +239,14 @@ function(zephyr_mcuboot_tasks)
       set_property(GLOBAL APPEND PROPERTY extra_post_build_commands COMMAND
         ${imgtool_sign} ${imgtool_args} ${imgtool_directxip_hex_command} ${imgtool_hex_extra} ${unconfirmed_args})
     else()
+      # Signature type determines key exchange scheme; ED25519 here means
+      # ECIES-X25519 is used. Default to HMAC-SHA512 for ECIES-X25519.
+      # Only NRF54L gets the HMAC-SHA512, other remain with previously used
+      # SHA256.
+      if(CONFIG_SOC_SERIES_NRF54LX AND CONFIG_MCUBOOT_BOOTLOADER_SIGNATURE_TYPE_ED25519)
+        set(imgtool_args ${imgtool_args} --hmac-sha 512)
+      endif()
+
       set_property(GLOBAL APPEND PROPERTY extra_post_build_commands COMMAND
         ${imgtool_sign} ${imgtool_args} --encrypt "${keyfile_enc}" --clear
         ${imgtool_directxip_hex_command} ${imgtool_hex_extra} ${unconfirmed_args})