[flashrom] Dual boot MCU

[Stuart Johnson]

I have an MCU that can boot from two locations of it's flash. The flash 
is 2097152 bytes, and the MCU will boot from location 0 or half way.  So 
I created a layout file, like so:

00000000:0000fffff bank0
00100000:0001fffff bank1

But flashrom is demanding the image to be written is the full 2097152 
bytes.  What am I missing?

flashrom -p .... --layout my_layout --image bank0 -w flash.bin

Error: Image size (1048576 B) doesn't match the flash chip's size 
(2097152 B)!