I want to use SHA384 instead of SHA256 to sign FIT images. 

diff --git a/poky/meta/classes/kernel-fitimage.bbclass b/poky/meta/classes/kernel-fitimage.bbclass
index bb2f3c4cc..d4f9dddf2 100644
--- a/poky/meta/classes/kernel-fitimage.bbclass
+++ b/poky/meta/classes/kernel-fitimage.bbclass
@@ -51,13 +51,13 @@ python __anonymous () {
 UBOOT_MKIMAGE_DTCOPTS ??= ""

 # fitImage Hash Algo
-FIT_HASH_ALG ?= "sha256"
+FIT_HASH_ALG ?= "sha384"

 # fitImage Signature Algo
 FIT_SIGN_ALG ?= "rsa2048"

 # Generate keys for signing fitImage
-FIT_GENERATE_KEYS ?= "0"
+FIT_GENERATE_KEYS ?= "1"

 # Size of private key in number of bits
 FIT_SIGN_NUMBITS ?= "2048"

I get below error,

ERROR: linux-obmc-5.8.17+gitAUTOINC+c26e1233f9-r0 do_assemble_fitimage: Execution of '/home/gangadhar/openbmc/build/tmp/work/linux-gnueabi/linux-obmc/5.8.17+gitAUTOINC+c26e1233f9-r0/temp/run.do_assemble_fitimage.17762' failed with exit code 255:
none
fit-image.its:8.26-20.19: Warning (unit_address_vs_reg): /images/kernel@1: node has a unit name, but no reg property
fit-image.its:17.32-19.27: Warning (unit_address_vs_reg): /images/kernel@1/hash@1: node has a unit name, but no reg property
fit-image.its:21.29-31.19: Warning (unit_address_vs_reg): /images/fdt@...: node has a unit name, but no reg property
fit-image.its:28.32-30.27: Warning (unit_address_vs_reg): /images/fdt@.../hash@1: node has a unit name, but no reg property
fit-image.its:36.30-50.19: Warning (unit_address_vs_reg): /configurations/conf@...: node has a unit name, but no reg property
fit-image.its:42.32-44.27: Warning (unit_address_vs_reg): /configurations/conf@.../hash@1: node has a unit name, but no reg property
fit-image.its:45.37-49.27: Warning (unit_address_vs_reg): /configurations/conf@.../signature@1: node has a unit name, but no reg property
uboot-mkimage Can't add hashes to FIT blob: -93
Unsupported hash algorithm (sha384) for 'hash@1' hash node in 'kernel@1' image node
WARNING: exit code 255 from a shell command.

Thanks & Regards,

Gangadhar