You could also just select the right chip definition :) Your log looks very much as if you got a MX25L64* with 4 kB sectors (e.g. MX25L6406E as you wrote) but the chip set definition you chose (MX25L6405) has 64 kB sectors in the smallest eraser.
Ah thank you, I didn't even notice...
I don't remember how I settled for the *05, however, attempting the 06E results in:
root@kiso:~# flashrom -p internal:laptop=force_I_want_a_brick -c MX25L640E -w coreboot.rom flashrom v0.9.9-r1954 on Linux 4.7.0-rc7-amd64 (x86_64) flashrom is free software, get the source code at https://flashrom.org
Error: Unknown chip 'MX25L640E' specified. Run flashrom -L to view the hardware supported in this flashrom version.
and the 06E appears in "flashrom -L"'s output...
Best regards, Arian