Add support for the JEDEC RES

Add support for the JEDEC RES (Read Electronic Signature and Resume from
Powerdown) SPI command to identify older SPI chips which can't handle

Since RES gives a one-byte identifier which is shared among many
different vendors and even different sizes, we want to match RES as a
last resort if RDID returns 0xff 0xff 0xff.

Corresponding to flashrom svn r235 and coreboot v2 svn r3320.

Signed-off-by: Carl-Daniel Hailfinger <>
Acked-by: Peter Stuge <>

This is a heavily reworked version of a patch by Fredrik Tolf, which was
Signed-off-by: Fredrik Tolf <>
4 files changed