The cpu, ram, screen, camera etc is pretty much the same specs, but the SoC went from an industrial grade one to a consumer grade one. Furthermore the FP6 only has USB2 and no display out. And last but not least, while the battery in the FP6 is a bit bigger, it is now a strange custom shape that you will never be able to find a new 3rd party replacement for in a few years, meaning all you will be able to buy is old stock from Fairphone itself that has already degraded to a certain extend.