Allows to keep a backup firmware in case active firmware is corrupted.
Also fix hsspi address warning.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
While "ok" is recognized in DT parsing, only "okay" is actually
mentioned as valid value. Replace it accordingly.
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>