kukui: include a dummy bootblock if BOOTBLOCK variable not set

Add a dummy bootblock to make sure size check is accurate during
`make buildall`.

The default size is picked from build 12769.0:
$ ls -al */coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:20 kodama/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:20 krane/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:20 kukui/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:33 damu/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:33 jacuzzi/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:33 juniper/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:33 kappa/coreboot/bootblock.bin
-rw-r--r-- 1 21504 Dec 19 02:21 flapjack/coreboot/bootblock.bin

BUG=chromium:1034518
TEST=1) make buildall # use dummy bootblock
     2) make BOARD=kukui # same as above, ~1.7k bytes left
     3) make BOARD=kukui BOOTBLOCK=/dev/null # empty bootblock,
                                               23k bytes left
     4) make BOARD=kukui BOOTBLOCK=a-large-file # fail early before
                                                  linking
BRANCH=kukui

Change-Id: I65c18f567dce0cb315e0cdc4f30ada5e83275d72
Signed-off-by: Ting Shen <phoenixshen@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1973550
Reviewed-by: Jett Rink <jettrink@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: Jack Rosenthal <jrosenth@chromium.org>

1 files changed, 0 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 41e87a173b..11dc09bcb7 100644
--- a/Makefile
+++ b/Makefile
@@ -60,10 +60,6 @@ config=$(out)/.config
 # If no key file is provided, use the default dev key
 PEM ?= $(BDIR)/dev_key.pem
 
-# If CONFIG_BOOTBLOCK is set, includes AP-FW bootblock in the EC image.
-# If no bootblock is provided, just pack an empty file.
-BOOTBLOCK ?=
-
 # Port for flash_ec. Defaults to 9999.
 PORT ?= 9999