MX flash MX29LV320T/B datasheet say reset is 0xf0. This change is very large impact then I use option.
MX CFI Flash machine
JEDEC CFI document written "Read Array data is FFh/F0h". I refer flashrom open source code. In this code probe_82802ab89 method is use 0xff and probe_jedec method is use 0xf0 by reset. probe_82802ab89 is 26 chips and probe_jedec is 128 chips in source code table. I think complete table is two big resource like as flashrom. I think option is good now.