Trying to flash kukui (issue should not be board specific though)
 - I have 2 servo_micro connected, only one has a servod instance running
 - I try to specify the appropriate servo_micro using `-p raiden_debug_spi:port=9999`.

$ bash -x ../flash_bios_kukui image.dev.bin 
+ PORT=9999
+ dut-control -p 9999 servo_micro_version
servo_micro_version:servo_micro_v1.1.9140-27e9ca8e6
+ dut-control -p 9999 cold_reset:on spi2_vref:pp1800 spi2_buf_en:on
+ sudo flashrom -n -p raiden_debug_spi:port=9999 -w image.dev.bin -V
flashrom v0.9.9  : 93107fc : Nov 16 2018 23:10:43 UTC on Linux 4.18.10-1rodete2-amd64 (x86_64)
flashrom was built with libpci 3.5.6, LLVM Clang 8.0.0 (/var/cache/chromeos-cache/distfiles/host/egit-src/clang.git 6601c8f525499269dba75f75bbd1ee2671aaa262) (/var/cache/chromeos-cache/distfiles/host/egit-src/llvm.git 36f54002c931a026f490f9fb074c11d91e3487a2), little endian
Command line (6 args): flashrom -n -p raiden_debug_spi:port=9999 -w -V image.dev.bin
Acquiring lock (timeout=180 sec)...
Opened file lock "/run/lock/firmware_utility_lock"
Lock acquired.
disable_power_management: Disabling power management.
Calibrating delay loop... OS timer resolution is 1 usecs, 2950M loops per second, 10 myus = 10 us, 100 myus = 100 us, 1000 myus = 999 us, 10000 myus = 10001 us, 4 myus = 4 us, OK.
Initializing raiden_debug_spi programmer
USB: Inspecting device (Bus 1, Address 10)
USB: Rejecting device because subclass = 80 != 81
USB: Rejecting device because subclass = 83 != 81
USB: Found matching device
USB: Inspecting device (Bus 1, Address 12)
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Inspecting device (Bus 1, Address 18)
USB: Rejecting device because subclass = 80 != 81
USB: Rejecting device because subclass = 83 != 81
USB: Found matching device
USB: Inspecting device (Bus 2, Address 1)
USB: Rejecting device because vid = 7531 != 6353
USB: Inspecting device (Bus 1, Address 11)
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Rejecting device because subclass = 255 != 81
USB: Inspecting device (Bus 1, Address 9)
USB: Rejecting device because vid = 1060 != 6353
USB: Inspecting device (Bus 1, Address 3)
USB: Rejecting device because vid = 1133 != 6353
USB: Inspecting device (Bus 1, Address 7)
USB: Rejecting device because vid = 3034 != 6353
USB: Inspecting device (Bus 1, Address 5)
USB: Rejecting device because vid = 1118 != 6353
USB: Inspecting device (Bus 1, Address 16)
USB: Rejecting device because class = 9 != 255
USB: Inspecting device (Bus 1, Address 8)
USB: Rejecting device because class = 3 != 255
USB: Inspecting device (Bus 1, Address 2)
USB: Rejecting device because vid = 6720 != 6353
USB: Inspecting device (Bus 1, Address 1)
USB: Rejecting device because vid = 7531 != 6353
Raiden: Found IN  endpoint = 0x83
Raiden: Found OUT endpoint = 0x03
...
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on raiden_debug_spi.
Probing for Generic unknown SPI chip (REMS), 0 kB: id1 0xff, id2 0xff
===
This flash part has status NOT WORKING for operations: PROBE READ ERASE WRITE
This flash part has status UNTESTED for operations: UNBOUNDED READ
The test status of this chip may have been updated in the latest development
version of flashrom. If you are running the latest development version,
please email a report to flashrom@flashrom.org if any of the above operations
work correctly for you with this flash part. Please include the flashrom
output with the additional -V option for all operations you tested (-V, -Vr,
-VE, -Vw), and mention which mainboard or programmer you tested.
Please mention your board in the subject line. Thanks for your help!
No -i argument is specified, set ignore_fmap.
Read is not working on this chip. Aborting.
FAILED
restore_power_management: Re-enabling power management.
+ dut-control -p 9999 cold_reset:off spi2_vref:off spi2_buf_en:off

I suspect flashrom is picking the wrong servo_micro raiden interface.