Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on linux_spi.
Probing for Generic unknown SPI chip (REMS), 0 kB: probe_spi_rems: id1 0xf0, id2 0x7
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI).

This flash part has status NOT WORKING for operations: PROBE READ ERASE WRITE

The chip is  mx25L6406EZNI-12gf   which I assume

would use  

Macronix      MX25L6406E/            PREW           8192  SPI


The command that gets the generic message is

sudo flashrom -r oldefi1.bin -V -p linux_spi:dev=/dev/spidev0.0

I put exactly what is listed as type and says unknown…

pi@pi0w:~ $ sudo flashrom -L | grep MX25L6406E/
Macronix      MX25L6406E/            PREW           8192  SPI
pi@pi0w:~ $ sudo flashrom -r oldefi1.bin -c "MX25L6406E/" -V -p linux_spi:dev=/dev/spidev0.0
flashrom p1.0-128-g4acc3f3 on Linux 4.14.71+ (armv6l)
flashrom is free software, get the source code at https://flashrom.org

flashrom was built with libpci 3.5.2, GCC 6.3.0 20170516, little endian
Command line (7 args): flashrom -r oldefi1.bin -c MX25L6406E/ -V -p linux_spi:dev=/dev/spidev0.0
Error: Unknown chip 'MX25L6406E/' specified.
Run flashrom -L to view the hardware supported in this flashrom version.