GalliumOS wiki is a good resource about this. They have your answer here:
https://wiki.galliumos.org/Hardware_Compatibility
You can do the coreboot firmware without the ME mod entirely within the Chromebook itself without needing a Raspberry Pi as an external programmer. Only when you want to eradicate the ME do you need the Pi.
Hardware wise: It's Ivy Bridge. You can flash an Ivy Bridge with Raspberry Pi+Flashrom because its chip is 3.3V.
I remember those having all kinds of driver issues and weird custom hardware that hamstrung efforts like this...