flash.sh: take a backup of known good firmware state to rollback to, revert to rollback if flashing fails for whatever reason.

Warn sleeps and give output. Removed recovery shell access after warning again that we are in known good state (TPMTOTP/HOTP will succeed on next reboot.

TODO: remove some output as part of subsequent QUIET cleanup

Signed-off-by: Thierry Laurion <insurgo@riseup.net>

Author: tlaurion

initrd/bin/flash.sh

@@ -21,7 +21,12 @@ case "$CONFIG_FLASH_OPTIONS" in
 esac
 
 flash_rom() {
-  ROM=$1
+  #backup firmware to rollback into in all failed attempts
+  warn "Taking a backup of firmware in case we need to rollback..."
+  $CONFIG_FLASH_OPTIONS -r /tmp/${CONFIG_BOARD}_bak.rom
+
+  ROM=$1 # ROM file to flash
+
   if [ "$READ" -eq 1 ]; then
     $CONFIG_FLASH_OPTIONS -r "${ROM}" \
     || recovery "Backup to $ROM failed"
@@ -47,9 +52,13 @@ flash_rom() {
       dd if=/tmp/pchstrp9.bin bs=1 count=4 seek=292 of=/tmp/${CONFIG_BOARD}.rom conv=notrunc >/dev/null 2>&1
     fi
 
-    warn "Do not power off computer.  Updating firmware, this will take a few minutes"
+    warn "Do not power off computer.  Updating firmware, this could take a few minutes"
     $CONFIG_FLASH_OPTIONS -w /tmp/${CONFIG_BOARD}.rom 2>&1 \
-      || recovery "$ROM: Flash failed"
+      || warn "$ROM: Flash failed, restoring rollback fimrware backup..." \
+				&& $CONFIG_FLASH_OPTIONS -w /tmp/${CONFIG_BOARD}_bak.rom \
+        && warn "$ROM: Flash failed, restored previous known good firmware state."
+      #TODO: there is a lot of output from flashprog here to suppress??? 
+      # But at least we didn't cause a brick...
   fi
 }
 
@@ -104,6 +113,6 @@ fi
 flash_rom $ROM
 
 # don't leave temporary files lying around
-rm -f /tmp/flash.sh.bak
+rm -f /tmp/flash.sh.bak /tmp/${CONFIG_BOARD}_bak.rom
 
 exit 0