diff --git a/scripts/image_signing/sign_official_build.sh b/scripts/image_signing/sign_official_build.sh
index 4e83a31..59033c2 100755
--- a/scripts/image_signing/sign_official_build.sh
+++ b/scripts/image_signing/sign_official_build.sh
@@ -913,7 +913,13 @@
 
   # Update the Kernel B hash in Kernel A command line
   local old_kerna_config="$(sudo dump_kernel_config "${loop_kerna}")"
-  local new_kernb_hash=$(sudo sha1sum "${loop_kernb}" | cut -f1 -d' ')
+  local old_kernb_hash="$(echo "$old_kerna_config" |
+    sed -nEe "s#.*kern_b_hash=([a-z0-9]*).*#\1#p")"
+  if [[ "${#old_kernb_hash}" -lt 64 ]]; then
+    local new_kernb_hash=$(sudo sha1sum "${loop_kernb}" | cut -f1 -d' ')
+  else
+    local new_kernb_hash=$(sudo sha256sum "${loop_kernb}" | cut -f1 -d' ')
+  fi
 
   new_kerna_config=$(make_temp_file)
   echo "$old_kerna_config" |