zinger: enable RO partition write-protection

Check the flash protection at startup, if the RDP is still at level 0
(no read protection) or if the RO partition is not write protected :
- set the write protection on the first 16KB of flash (4 LSB of WRP0)
- push the RDP to level 1, so SWD/serial monitor needs to fully erase
  the part before re-writing the code or the write-protection.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=samus
BUG=chrome-os-partner:34935
TEST=dump the content of the option bytes.

Change-Id: I11af64365a6fbc34327b2e463eb8e2d369ffacd2
Reviewed-on: https://chromium-review.googlesource.com/238262
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>
Trybot-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/util/flash_ec b/util/flash_ec
index 934af83770..3278f1d8fd 100755
--- a/util/flash_ec
+++ b/util/flash_ec
@@ -333,7 +333,7 @@ function flash_stm32() {
 	# Reset the EC
 	ec_reset
 	# Unprotect flash, erase, and write
-	${STM32MON} -d ${EC_UART} -u -e -w "${IMG}"
+	${STM32MON} -d ${EC_UART} -U -u -e -w "${IMG}"
 }
 
 function flash_stm32_dfu() {